HTML & Web Design

Introduction & Intermediate Levels

Day One

T.I. McLaughlin

mcse, mct, b-admin, a+, webmaster

http://tom.mclaughlin.net

Table of Contents

Basic Concepts.............................................................................................................................. 5

Tags:............................................................................................................................................................................................ 5

Head:............................................................................................................................................................................................ 5

Title:............................................................................................................................................................................................. 5

Body:............................................................................................................................................................................................ 5

Headings:.................................................................................................................................................................................... 5

Paragraphs:................................................................................................................................................................................ 5

Alignment:.................................................................................................................................................................................. 6

Lists:............................................................................................................................................................................................ 6

A Basic HTML Document............................................................................................................ 7

<P> Paragraph command......................................................................................................................................................... 7

<BR> Line Break command.................................................................................................................................................... 7

<Center> command................................................................................................................................................................... 7

<ALIGN> command................................................................................................................................................................... 7

<I> Italicize (Emphasis or Citation) command:.................................................................................................................... 8

<B> Bold (Strong) command:.................................................................................................................................................. 8

<UL> Indentation (Blockquote) command:............................................................................................................................ 8

<H1> (Big) command:............................................................................................................................................................... 8

<HR> command:......................................................................................................................................................................... 8

Lists.............................................................................................................................................. 10

Ordered Lists........................................................................................................................................................................... 10

Unordered Lists....................................................................................................................................................................... 10

Directory lists.......................................................................................................................................................................... 11

Definition Lists........................................................................................................................................................................ 11

Hyperlinks................................................................................................................................... 12

Local Links.............................................................................................................................................................................. 12

Absolute Links........................................................................................................................................................................ 12

Bookmark hyperlinks:.......................................................................................................................................................... 12

Mailto: command..................................................................................................................................................................... 13

Embedding Images...................................................................................................................... 14

<IMG SRC> command:........................................................................................................................................................... 14

Hyperlink an Image:............................................................................................................................................................... 14

Tables:......................................................................................................................................... 16

Fixing Column Widths:.......................................................................................................................................................... 18

Setting Table Borders:........................................................................................................................................................... 18

Forms:.......................................................................................................................................... 19

Form Elements......................................................................................................................................................................... 19

Optional attributes are:.......................................................................................................................................................... 20

Form Submission.................................................................................................................................................................... 21

The form-urlencoded Media Type.................................................................................................................................... 21

Example Form Submission:................................................................................................................................................... 21

CGI-BIN...................................................................................................................................... 24

HTML & WEB DESIGN - DAY TWO....................................................................................... X

Image Maps................................................................................................................................. 25

Advanced Formatting.................................................................................................................. 26

Controlling Document Backgrounds.................................................................................................................................. 26

The Bgcolor Attribute............................................................................................................................................................ 26

Text Attributes......................................................................................................................................................................... 26

The Link, Vlink, And Alink Attribute................................................................................................................................ 26

Controlling Individual Text Attributes:.............................................................................................................................. 26

Preventing Line Breaks:....................................................................................................................................................... 27

Multi-Column Text:................................................................................................................................................................ 27

Scrolling:.................................................................................................................................................................................. 27

Margins:................................................................................................................................................................................... 27

Buttons:..................................................................................................................................................................................... 28

Inline Video:............................................................................................................................................................................. 28

Embedded Objects:..................................................................................................................... 28

Frames......................................................................................................................................... 29

NOFRAMES............................................................................................................................... 30

Floating Frames:.......................................................................................................................... 30

META TAGS............................................................................................................................... 31

Abstract..................................................................................................................................................................................... 31

Introduction.............................................................................................................................................................................. 31

The META Tag......................................................................................................................................................................... 31

HTTP-EQUIV........................................................................................................................................................................... 31

NAME........................................................................................................................................................................................ 32

CONTENT................................................................................................................................................................................ 32

Cataloguing an HTML document......................................................................................................................................... 32

Page Transitions..................................................................................................................................................................... 32

Search Engines:...................................................................................................................................................................... 32

Cascading Style Sheets............................................................................................................... 33

The Contents of a Style Sheet............................................................................................................................................... 33

Linking a Style Sheet to a Page........................................................................................................................................... 33

To link a page to an external style sheet............................................................................................................................. 33

Cascading Style Sheets Tip:................................................................................................................................................. 34

Inline Video:................................................................................................................................ 34

Embedded Objects:..................................................................................................................... 34

Cookies........................................................................................................................................ 35

What is XML?............................................................................................................................. 37

Introduction to DHTML............................................................................................................. 38

JAVA AND JAVASCRIPT........................................................................................................ 39

What is needed?...................................................................................................................................................................... 39

Flash - Introduction..................................................................................................................... 40

Shockwave - Introduction............................................................................................................ 40

E-Commerce - Introduction......................................................................................................... 41

A Tutorial on E-commerce..................................................................................................................................................... 41

WebMonkey's HTML Cheat Sheet........................................................................................... 41

Legaleese:

This document mentions several HTML viewers and companies by name, this is not intended as an endorsement of any company or product. All trademarks are recognized as belonging to their respective owners.

Introduction

Publishing information electronically requires some medium to present the information to the reader. A graphics viewer is used to access pictures, Example. An HTML viewer (or web browser as they are commonly known) is a program which presents electronic documents, in HTML format, to the reader.

The hypertext Mark-up Language (HTML) is a simple data format used to create formatted electronic documents with hyperlinks to other documents and resources (this hyper linking to other documents is known as hypertext) that are portable from one computer platform to another. That is, an HTML document created on a PC may also be read by a user of a UNIX machine or an Atari, Macintosh and so on. The term "mark-up" is a printing expression describing the process of putting together words and picture to form a document. HTML, is used electronically to put together words (text) and pictures (images) into a finished presentation document. Recent innovations mean that video clips and

sound can also be added, making HTML a full multimedia publishing medium.

You will probably be familiar with the idea of formatted documents, these are produced by word processors. A formatted document has a variation in its appearance. It looks pretty. Where as an unformatted document has all the text in one style. Links to other documents and resources may be a newer idea for you.

A standard formatted document simply conveys information, and may suggest other sources of information to the reader. A hypertext document does the same, but where a suggestion of other information is made a provision is made for the reader to click the mouse button or press a keyboard button and the program being used to view the hypertext document will load and display the linked document.

Example, this is a formatted text document that you are reading. If I wish to refer you to another document, titled "order.doc" to view that document you need to select the file option from your viewer software, and open the named file. With a hypertext document, you could simply point the mouse to the words "order.doc" which would be displayed in a different color, and click the mouse button to ask the viewer software to load and display the document. Of course as the author of the document, I would have to include some instruction to the viewer software that would enable you to do that. These instructions form part of the HTML language. They are called "hyperlinks" and provide a path to other documents or resources, called Uniform Resource Locations, or URLs for short.

HTML documents are viewed with an HTML viewer, or "web browser" as they are starting to be known in PC circles. The most common HTML viewers used by PC users are Microsoft's Internet Explorer and Netscape's Navigator. But there are others. Mosaic, by NCSA is available in a number of custom Internet packages including Quarter-deck's Internet connectivity package and is perhaps the next most widely used. What is less well known is that all HTML viewers present HTML documents slightly differently. Although HTML is specified, HTML viewers do not pay too much attention to the official specifications and manufacturers have added support (both documented and not!) for a variety of additional features and commands including built-in Java compilers to understand Java code and support for Frames.

If you are publishing your document for a known audience, you should know which HTML viewer will be used to access the document, and you should be aware of the facilities supported by that viewer. When publishing for the World Wide Web you should remember that your audience is comprised of millions of people, with dozens of different HTML viewers, which whilst supporting basic features, have many discrepancies in their support of advanced features. Some may not even have the ability to display images. So while this e-text describes and illustrates many features found only in one or two HTML viewers, it should not be viewed as a recommendation to use these features for general HTML publishing.

Basic Concepts

As with any aspect of computing, HTML introduces some new concepts and jargon. It is necessary to be familiar with these basic terms in order to understand the rest of this document.

Tags:

Tags provide instructions to an HTML viewer about elements such as headings, paragraphs, lists, character highlighting, and hyperlinks. Most HTML elements are identified in a document as a start-tag followed by an end tag. The start-tag provides the HTML viewer with the element name and attributes, followed by the content. The end-tag

tells the HTML viewer about the end of the element. Start-tags are delimited by `<'and `>'; end tags are delimited by `</' and `>'.

Example:

<H1>This is a Heading</H1>

In the above example the start-tag is <H1> and the end-tag is </H1>

Comments:

To include comments in an HTML document, use a comment declaration. The entire comment declaration is ignored.

Example:

<!-- This is a multiple-line

comment -->

Head:

The head of an HTML document, defined by the start-tag <HEAD> and delimited by the end-tag </HEAD>, is where heading information about the document goes. The heading information is an unordered collection of information about the document, such as the title of the document.

Example:

<HEAD>

<TITLE>Document Title</TITLE>

</HEAD>

This example declares the document title to the HTML viewer as "Document Title".

The title element contains your document title and identifies its content in a global context. The title is displayed somewhere on the HTML viewer window (usually at the top), but not within the document area. The title is also used for book marking and during a WAIS search of a server and should be less than 64 characters long.

Title:

Every HTML document must contain a TITLE element. The title should identify the contents of the document in a global context. A short title, such as "Introduction" may be meaningless out of context. A title such as "Introduction to HTML Elements" is more appropriate. An HTML viewer may display the title of a document in a history list or as a label for the window displaying the document.

Example:

<TITLE>Put something descriptive in the Title area</TITLE>

Body:

The BODY section of an HTML document is where the text to be displayed is placed. This is the largest section of an HTML document, and is defined by the start-tag <BODY> and terminated by the end-tag </BODY>

Example:

<BODY>

This is displayed in the HTML viewer text window

</BODY>

Headings:

Headings are generally displayed in a larger type-face (or font) than the main text. HTML provides two systems for declaring a heading.

The old system, which is recognized by all HTML viewers, supports six sizes of text declared by the start-tags <H1>, <H2>, <H3>, <H4>, <H5> and <H6>, each of which has a corresponding end-tag such as </H1>, </H2> and so on. The text sizes range from <H1> the biggest, through <H3> the default size to <H6> the smallest.

Example:

<H1>This is a large heading</H1>

<H3>This is in the normal default size</H3>

<H6>This is very small!</H6>

Paragraphs:

Unlike most word processors, HTML viewers ignore carriage returns, and additionally multiple spaces are reduced to a single space. The paragraph command (<P> and </P>) tells the HTML viewer that the text contained within the start-tag and end-tag is a paragraph. Paragraphs are displayed by the HTML viewer separated by a single blank line from the preceding items.

Example:

<P>

This is a paragraph.

This second line is actually displayed by an HTML viewer on the same line as the previous line, as the carriage return is ignored.

</P>

<P>

This second paragraph is displayed with a single blank line between it and the previous paragraph.

</P>

This results in the following to be displayed by an HTML viewer:

This is a paragraph. This second line is actually displayed by an HTML viewer on the same line as the previous line, as the carriage return is ignored. This second paragraph is displayed with a single blank line between it and the previous paragraph.

Alignment:

Text and images may be aligned to the left, to the right, centered or justified.

Lists:

A list is simply a list of items. The HTML viewer automatically starts each list item on a new line, and handles list numbering and bulleting depending upon how the HTML author has declared the list.

Hyperlinks:

Hyperlinks are a provision allowing the user of the HTML document to navigate through the document and to external resources. Hyperlinks may be local, allowing navigation within the currently loaded document, or external providing access to other documents not loaded and resources such as ftp servers and mail servers. These generally come in blue text and underlined

A Basic HTML Document

A simple HTML document is comprised of the following components:

NOTE: Use lower case whenever possible, the examples are upper case for emphasis.

<HTML> A HTML declaration tag,

<HEAD> A heading tag,

<TITLE> A title, such as within the Head.

<BODY> A body declaration tag:

The main body of the document - this is what the people browsing will see.

A body termination tag </BODY> and finally an HTML termination tag: </HTML>

Example:

<HTML>

<HEAD>

<TITLE>Example HTML Document</TITLE>

<BODY>

This is an example HTML document.

</BODY>

</HTML>

Adding Headings:

Headings can be added to an HTML document with the heading tags in the BODY section;

<H1> through <H6>.

Example:

<HTML>

<HEAD>

<TITLE>Example HTML Document</TITLE>

<BODY>

<H1>Main Heading</H1>

<P>

This is an example HTML document.

</P>

</BODY>

<P> Paragraph command

Notice the use of the paragraph start-tag <P> and end-tag </P> which tells the HTML viewer to display the text as a new paragraph, and not as a continuation of the heading line.

Simple Formatting

HTML viewers do not recognize carriage-returns in the text. Instead, they display the text as continuous lines, breaking each line at a word end so that it fits in the text window. This is known as word-wrap. You can force a line break with the HTML tag <BR>.

<BR> Line Break command

Example:

This is line one<BR>This is line two

Which displays as:

This is line one

This is line two

<Center> command

Centering a line of text is also easy. The HTML tag <CENTER> causes all subsequent text and images to be displayed in the centre of the text window until a </CENTER> end-tag is reached.

Example:

<H1>Main Heading</H1>

<P>

This is an example HTML document.

</CENTER>

If you just want to center a single heading, you can use the "align=" command within the heading tag, Example: <H1 align=center>

The example HTML document would then look like this:

<H1 align=center>Main Heading</H1>

<P>

This is an example HTML document.

<ALIGN> command

The ALIGN= command may also be added to the paragraph tag, <P> to align an entire paragraph, Example:

<P ALIGN=CENTER>In addition to defining the size of the typeface used to display text (heading), HTML also supports bold, italic, strikethrough, underline, subscript and superscript formats. The following example illustrates the popular formatting tags:

<H1 align=center>Main Heading</H1>

<P>

Paragraphs are contained within a <P> and </P> tag pair, although the end-tag </P> is not needed if another paragraph starts with a <P> start-tag. Paragraphs may be aligned, with the "align=" command,

Example:

A standard paragraph

<P>

Left aligned paragraph

Center aligned paragraph

Right aligned paragraph

<I> Italicize (Emphasis or Citation) command:

Text defined as italic. An Italic address is declared by the tag pair <I > and </I >,

Example:

<I>

This text will normally be displayed in italic.

</I>

<B> Bold (Strong) command:

Strong text is declared by the tag pair <B> and </B> and is usually displayed in bold.

<UL> Indentation (Blockquote) command:

Text defined as a UL or "Blockquote" for older browsers is displayed as a new paragraph, and usually displayed indented from the left margin, and with some HTML viewers in a unique typeface. A UL is declared by the tag pair: <UL> and </UL>, remember it's not the <I> command - that's italicize!

Example:

<UL>

This section will normally be displayed indented.

</UL>

<CODE> Source Code command:

Source code is declared by the tag pair <CODE> and </CODE> and is usually displayed in a fixed width font, though this may be changed by the user of the HTML viewer. Generally used to show how the coding is done and not having the browser actually do it.

<H1> (Big) command:

Big text is declared by the tag pair <H#> and </H#> and is usually displayed larger than the ordinary text and has up to 6 sizes.

Dividers

HTML provides three basic ways of dividing a document window: Paragraphs, Line Breaks, and Horizontal Rules.

Line breaks are enforced with the <BR> tag. When an HTML viewer encounters the <BR> tag, the cursor is moved down one line and to the left of the window. If an alignment is in operation, the next displayed line will be aligned correctly.

<HR> command:

Horizontal rules are affected with the <HR> tag. This tells the HTML viewer to display a graphical horizontal line across the entire width of the window. The form of the rule can be amended with the optional "size=", "width=", "noshade" and "align=" parameters.

The vertical thickness of the horizontal rule can be defined by adding a size= parameter to the <HR> tag. The number following the size= parameter tells the HTML viewer how many vertical pixel lines to use for the rule.

Example:

By default, a horizontal rule extends the entire width of the window. The width= parameter may be used to specify the horizontal width of the rule either in pixels, or as a percentage of the window width:

<HR width=100> or <HR width=50%> <- this one is preferable

Horizontal rules are usually aligned in the center of the window, or if an alignment is in force, they follow the rules of the current alignment. This may be overridden by the align= parameter,

Example:

Finally, horizontal rules are displayed in a 3d representation. This can be changed to a solid thick 2 dimensional line with the noshade parameter:

As usual, these parameters can be mixed together,

Example:

Lists

HTML supports a number of types of list: Ordered, Unordered, Definition, Menu and Directory.

Ordered lists are displayed one item per line, with a sequential numbering system to the left of each item. An ordered list is declared by the start-tag <OL> and terminated with the end-tag </OL>. Individual items are declared with the tag <LI>.

Ordered Lists

Example:

<OL>

<LI> Item one

<LI> Item two

<LI> Item three

</OL>

Which is displayed by an HTML viewer as:

1. Item one

2. Item two

3. Item three

The numbering system may be amended with the optional TYPE= command.

The valid types are A,a,I,i, giving the following displays:

Example:

Capital A <OL TYPE="A">

A. Item one

B. Item two

C. Item three

Small A <OL TYPE="a">

a. Item one

b. Item two

c. Item three

Numbered Lists <OL TYPE="1">

1. Item One

2. Item Two

3. Item Three

Roman Capital <OL TYPE="I">

I. Item one

II. Item two

III. Item three

Roman Small <OL TYPE="i">

i. Item one

ii. Item two

iii. Item three

The starting number may be defined by adding a START= command to the ordered list declaration,

Example:

Which then produces the following display:

100. Item one

101. Item two

102. Item three

The numbering order may be further amended during the list by adding a VALUE= command to a list item declaration,

Example:

<LI> Item one

<LI VALUE=500> Item two

<LI> Item three

</OL>

Which produces the following display:

100. Item one

500. Item two

501. Item three

Unordered Lists

An unordered list is displayed without numbering, but with bullets,

Example:

<UL>

<LI> Item one

<LI> Item two

<LI> Item three

</UL>

Which is displayed by an HTML viewer as:

· Item one

· Item two

· Item three

Some HTML viewers allow the bullet style to be redefined with a TYPE=command, accepting the values DISC, CIRCLE and SQUARE,

Example:

<LI> Item one

<LI> Item two

<LI> Item three

</UL>

Directory lists

Directory lists are specified by the <DIR> element, are similar to unordered lists. They represent a list of short items, typically up to 20 characters each. Items in a directory list may be arranged in columns, typically 24 characters wide, but may not be nested (unlike

other lists). Some HTML viewers will further display directory lists in a different font to other lists.

Definition Lists

Definition lists are used for listing terms and their definitions. A definition list is declared with the start-tag <DL>, and rather than using the list item tag <LI>, it uses a pair of tags, data-term and data-definition, <DT> and <DD> respectively. The data-definition is

displayed indented from the preceding data-term.

Example:

<DL>

<DT>Definition one

<DD> Description of definition one which can wrap around to more than one line

<DT>Definition two

<DD> Description two which can wrap around<BR>to more than one line

<DT>Definition three

<DD> Description of definition three

</DL>

Which is displayed by an HTML viewer as:

Definition one

Description of definition one which can wrap around to more than one line

Definition two

Description of definition two which can also wrap around to more than one line

Definition three

Description of definition three

Hyperlinks

Hyperlinks enable the user of an HTML document to navigate through the currently loaded document (using local hyperlinks) and to external resources.

All hyperlinks are defined in the HTML source code by anchors. An anchor is the following HTML code: <A..>. There are local links and absolute links.

Local Links

A local link is one that will bring the person to another page on your website.

Example:

<A HREF="page2.html">Click Here For Page Two</A>

Absolute Links

An absolute link is one that will take the person to another website.

Example:

<A HREF="http://tom.mclaughlin.net>Click Here for Tom's Website</A>

An image could be used instead of the text, by replacing the hyperlink display text with an inline image command,

Example:

Bookmark hyperlinks:

Local hyperlinks, known as "Fragment Identifiers", are defined in a hypertext address by a # character following the resource. If navigation is required within the local document, the resource may be omitted so that a local hyperlink may look like:

<A HREF="#introduction">Introduction</A>

Selecting this hyperlink will cause the HTML viewer to search the current document for a declaration of "introduction". This declaration is achieved with the anchor name tag <A NAME=>, like this:

Notice that the <A NAME=> tag does not have an end-tag, and is case insensitive. It doesn't matter if the anchor name is declared as "INTRODUCTION" or "Introduction" or even "introDuction" it will still be found by a hyperlink to "#introduction". Local hyperlinks can be added to hyperlinks to external documents to force the HTML viewer to load an external document and then navigate straight to a desired section within that document.

Example:

This will create a hyperlink to the anchor "section_3" within the HTML document "part_two.htm". The following HTML document illustrates the use of local hyperlinks to form a table of contents to a document. Although this document is very short, you can see how the principle can be applied to longer and more complex documents.

*Copy and Paste this part unto Notepad and save it as "jumper.html"*

<HTML>

<HEAD>

</HEAD>

<BODY>

<TITLE>Local Hyperlink Example HTML document</TITLE>

<P>

<H2>Contents</H2>

<OL>

<LI><A HREF="#AEGIR">Aegir</A>

<LI><A HREF="#AESIR">Aesir</A>

<LI><A HREF="#ASGARD">Asgard</A>

<LI><A HREF="#BALDER">Balder</A>

</OL>

<A NAME="AEGIR"><I><B>Aegir</B></I>

<P>

In Norse mythology, Aegir is the god of the sea.

<P>

<A NAME="AESIR"><I><B>Aesir</B></I>

<P>

The Aesir were the principal gods in Norse mythology.

They lived in <A HREF="#ASGARD">Asgard</A>.

<P>

<A NAME="ASGARD"><I><B>Asgard</B></I>

<P>

In Norse mythology Asgard was the home of the gods.

<P>

<A NAME="BALDER"><I><B>Balder</B></I>

<P>

In Norse mythology, Balder was the son of Odin and Freya and husband of Nanna,

and the best, wisest, and most loved of all the gods. He was killed, at Loki's instigation, by a twig of mistletoe shot by the blind god Hodur.

<P>

</BODY>

</HTML>

*End Copy and Paste*

Netscape introduced a number of new commands for hyperlinks. TARGET=can be used to open the hyperlink document in a new instance of the HTML viewer, or a specified frame. More about frames in Advanced HTML.

Example:

<A HREF=next.htm TARGET=_BLANK>Next Document</A>

When the hyperlink "Next Document" is selected, the document "next.htm" will be opened and displayed in a new instance of the HTML viewer.

Hyperlinks are not restricted to other HTML documents. They can be used to access news servers, gopher servers, send mail and access ftp servers.

Mailto: command

A hyperlink to send mail uses the URL "mailto:"

Example the following link attempts to send an email message to me:

<A HREF="mailto:tom@mclaughlin.net">Feedback</A>

Some HTML viewers will also support the addition of an optional subject, to save the user typing it in.

Example:

<A HREF="mailto:tom@mclaughlin.net" ?SUBJECT=Feedback>Feedback</A>

Files can be sent to the user through FTP links, to send a specific file, use something like:

< A HREF="ftp://server/path/filename">Download HTML notes zipped file</A>

Example:

Download <a href="ftp://tom.mclaughlin.net/htmlnotes.zip">HTMLnotes.ZIP</A>

The HTML viewer will usually contact the FTP server, and attempt to connect using the name "anonymous" and sending the user's email address as a password.

Embedding Images

What would a website be like without pictures? Boring! Might as well have a text file up to read. While it may be good to have a lot of information up on the website, it depends of course on your target audience, but pictures do enhance even technical pages.

My suggestion is have no more then 3 pictures per page. Why? Because of loading times, and distraction from the fact of what you are trying to say to the viewer. Remember a picture is worth a 1000 words, so how many would 4 or more pictures worth? I think you get my point, that would be a lot of reading!

Pictures come in 3 standard formats for the Internet: *.JPG, *.BMP, *.GIF

- JPG, or JPEG's (Joint Photographic Experts Group) are great for clarity and footprint size, they are compressed files but don't loose any of the sharpness of the picture. I recommend this for most of your pictures.

- BMP (Bit Maps) are great for paintings, or cartoon type characters. If your picture has any letters in it, such as "SALE!" I would suggest you would want to use the BMP as the JPG would square off the letters.

- GIF (Graphics Interchange Format) is used for motion type pictures. You know, the one's with the running dog across the screen? Plus you can make rotating banners with it via GIF89, usually included with Front Page or other programs.

Most newer HTML viewers can display pictures, called images, in various forms. The most popular being GIF and JPEG formats. The procedure for telling the HTML viewer to display the image is the same regardless of the image format:

Example:

Will cause the HTML viewer to display the image "picture.gif".

Some HTML viewers cannot display images, so you can provide text which will be displayed by these viewers instead of the image by including it with the "alt=" parameter, this is a good habit to get into, we will discuss this later under Search Engine on the Advanced Level of HTML.

Example:

The image may be aligned in relation to the surrounding text using the optional "align=" parameter. If no alignment parameter is specified, text following the image will be displayed at the bottom right of the image. Different HTML viewers handle the alignment of text and images differently, so be careful!

The size of the image can be declared to the HTML viewer with the optional "width=" and "height=" parameters. If these are not specified, the HTML viewer will display the image at its full size. If however you specify these size parameters, the image will be displayed

to the specified size in pixels.

Example:

Remember for better search engine positioning, put the Alt (alternate) command with your picture!

<IMG SRC> command:

To insert a picture into your website, you need the <img src="picutrename.jpg> command. You can place graphic images on your pages, if the graphic image is stored as a separate file on your server or some other server on the net. The file format must be readable by the browser.

There are two common types of images: the ".GIF" or ".JPG" formats. While .gif pictures are common, I have found the .jpg gives the same image, but is smaller in file size, meaning quicker loading time and less file space taken up on your homepage.

In it's simplest form, the tag to cause a graphic to be placed on the page looks like this: "<img src="Ted2.jpg">"

You can control the position of the image. The most basic way to do this is to treat it as text. For example, surrounding the image tag with "<center> Ted2.jpg </center>" tags. If you want the image to have a name while loading, put a "alt=name" in the command line, or even what size you wish to have it displayed at, then the following commands must be added:
<center><img src="Ted2.jpg" alt=Freddie width=100 height=100><center>

that will control the size and position of the graphic, you can experiment to what size the graphic can be by increasing or decreasing the numbers.

Hyperlink an Image:

If you wish to use the graphic as a hyperlink to another page, then "surround" the image command with the hyperlink command you learned earlier.

Example:

<a href=page2.html><img src=Ted2.jpg alt="Freddie the Teddie"></a>, and if you don't wish to have a border around the image use: <img src=Ted2.jpg border=none alt="Freddie the Teddie"> command.

One very important thing to remember always spell the name of the image EXACTLY the way it is saved as. Meaning if it has a Capital letter, or if it is all lower case, then it has to be called up that way. I get a lot of requests from people "I can't get my graphic to show, how come?"...well their spelling and capitalization is wrong.

Like the teddy bear image, it's called "Ted2.jpg" notice the Captial "T" in Ted2.jpg. If I went then and by accident used a small "t" instead <img src=ted2.jpg> it will show up as what is called a "broken image.

There is much more to be said about graphic images, since they are a key element in really good pages, and can also detract from your page by making it very "slow" or crowded. Use graphics sparingly, or at the most, use a lot of ".jpg" formats. One urge every newbie has is to put EVERYTHING on their first homepage page like me, yes, I admit I did it, so after about 3 hours of loading your page finally is able to view!

Learn to make more pages, and less graphics! Or use design software to make “thumbnails” (smaller versions of the pictures) and link those thumbnails to the larger picture.

Good graphic programs are Adobe Photoshop 6.0 or Print Shop Pro 7 (almost the same in quality and cheaper in price as Adobe).

Tables:

The HTML table tags enable an HTML author to display information in a tabular format. A table is a grid of cells, each cell may contain a mixture of text and images and be a different size to the other cells in the table.

A table is declared within the start-tag <TABLE> and end-tag </TABLE>. You can specify a border and its width in pixels for the table by adding a BORDER= command to the table start-tag,

Example:

Will give the displayed table a border 1 pixel wide. A wider border can be forced with BORDER=10

Example:

The spacing between the cells can also be determined in pixels with the CELLSPACING= command. If you want a 10 pixel gutter between the table cells add the command CELLSPACING=10 to the table start-tag:

The spacing between the cell walls and the enclosed data can also be determined in pixels with the CELLPADDING= command. If you want a 10 pixel gutter between the table cell walls and the data in the cell add the command CELLPADDING=10 to the table start-tag:

Finally the width of the table can be expressed in pixels, or as a ratio of the document window width with the WIDTH= command;

Putting this together we might want a table 200 pixels wide, with a cell spacing of 5 pixels and a border of 4 pixels width. The following table start-tag will achieve this:

A caption can be included for the table with the caption tags <CAPTION> and </CAPTION>. The text or image contained within the caption tags will usually be displayed centred at the top of the table, just above the top border line. You can force the caption to be displayed below the table by adding the ALIGN=BOTTOM command to the caption start-tag,

Example:

<TABLE>

<CAPTION>This caption displays above the table</CAPTION>

</TABLE>

<TABLE>

<CAPTION ALIGN=BOTTOM>This caption displays below the table</CAPTION>

</TABLE>

Table cells are defined in terms or rows and within the rows, columns (either "table header" or "table data" cells). A table row is defined within the tags <TR> and </TR>,

Example:

<TABLE>

<TR>

This is a table cell...

</TR>

</TABLE>

A table header column is defined within a row by the tags <TH> and </TH>, Example;

<TABLE>

<TR>

<TH>

This is a table!

</TH>

</TR>

</TABLE>

Table header cells are, by default, displayed in BOLD and aligned in the center both horizontally and vertically.

A table data column is defined within a row by the tags <TD> and </TD>,

Table data cells are, by default, aligned left and vertically centered within the cell.

Each table column may have individual alignment characteristics defined by the ALIGN= and VALIGN= commands which override the default settings. The ALIGN= command can be used to force the display to the left or right of the cell, and the VALIGN= command to force the display to the top or bottom of the cell

Example:

<HTML>

<HEAD>

<TITLE>Table Example</TITLE>

</HEAD>

<CAPTION ALIGN=BOTTOM>Table Caption</CAPTION>

<TR>

<TD>

Cell One is aligned to the left and in the center vertically

</TD>

<TD>

Cell Two

<P>has multiple lines

<P>in it

<P>and is displayed to the left of the cell

</TD>

</TR>

<TR>

Cell Three is centered horizontally,

<P>at the top of the cell

</TD>

Cell Four is another

<P>multiple line cell

<P>displayed to the right

</TD>

</TR>

</TABLE>

</BODY>

</HTML>

You can stop the HTML viewer from word-wrapping the text within a cell by adding the command NOWRAP to the cell definition,

Example:

<TD NOWRAP>This text will be displayed as one long line</TD>

The size of the cell can be determined, to a degree, with the COLSPAN=and ROWSPAN= commands. These tell the HTML viewer how many columns and rows the cell is to span in relation to the rest of the table.

Example:

<HTML>

<HEAD>

<TITLE>Simple Table</TITLE>

</HEAD>

<BODY>

<TR><TH colspan=3>Protoplasm</TH></TR>

<TR><TH>Plants</TH><TH>Invertebrates</TH><TH>Vertebrates</TH></TR>

</TABLE>

</BODY>

</HTML>

Blank or empty cells can be defined to force cells within a row to the right,

Example:

Microsoft's Internet Explorer supports use of the BGCOLOR= command in the <TABLE> tag. It allows the background colour of the table to be specified using a standard rrggbb hex triplet.

Example:

Microsoft's Internet Explorer includes support for the BORDERCOLOR=command which sets the border colour of the table. It takes as a parameter a rrggbb hex triplet. It is necessary for the BORDER attribute to be present in the main <TABLE> tag for border colouring to work.

Microsoft's Internet Explorer allows use of the BORDERCOLORLIGHT=command to set independently, the lighter colour to be displayed on a 3-dimensional <TABLE> border. It is the opposite of BORDERCOLORDARK. It takes a colour parameter defined by a rrggbb hex triplet. It is necessary for the BORDER attribute to be present in the main <TABLE> tag for border colouring to work.

Microsoft's Internet Explorer allows use of the BORDERCOLORDARK=command to set independently, the darker colour to be displayed on a 3-dimensional <TABLE> border. It is the opposite of BORDERCOLORLIGHT. It takes as a parameter a colour defined by a rrggbb hex triplet. It is necessary for the BORDER attribute to be present in the main

<TABLE> element for border colouring to work.

NOTE: The BGCOLOR, BORDERCOLOR, BORDERCOLORLIGHT and BORDERCOLORDARK attributes can also be used in <TH>, <TR> and <TD>tags, with the colour defined in the last element over-riding those defined before. E.g. if a <TD> element contains a BORDERCOLOR attribute setting, the setting specified will be used instead of any colour settings that may have been specified in the <TR> element, which in turn over-rides any colour settings in the <TABLE> element.

Some HTML viewers support the placing of background images inside the <TABLE>, <TH> and <TD> tags. If used in the <TABLE> element, the image will be tiled behind all of the table cells.

Example:

Fixing Column Widths:

The HTML viewer property of displaying images within table cells can be exploited to create fixed column widths in a table, where the data contained within the columns varies in width. Normally, the HTML viewer generates columns based upon the widest element in the table column, creating uneven column widths. However, by forcing one cell in each column to a desired width, as wide or wider than the widest cell, you can create even column widths. One way to do this is to create a GIF image, of a single colour 2 x 2 pixel in size and make it transparent. Being so small this image will occupy a negligible amount of disk space and load even remotely very fast. Then this image can be used as an invisible element within a table cell to widen the cell as desired. The following example does not work with Mosaic, which does not support the image HEIGHT= and WIDTH= commands within a table cell, but it does work with Internet Explorer:

<HTML>

<HEAD>

<TITLE>Table</TITLE>

</HEAD>

<BODY>

<CAPTION><H1>Fixed Width Table Demonstration</H1></CAPTION>

<TR>

<TD><IMG SRC=spacer.gif height=1 width=300><BR>1.00</TD><TD><IMG

SRC=spacer.gif height=1 width=300><BR>8654.88</TD><TD><IMG

SRC=spacer.gif height=1 width=300><BR>7430456.78</TD> <TR>

</TABLE>

</BODY>

</HTML>

Setting Table Borders:

Internet Explorer supports the use of the FRAME= command which requires the BORDER= command to be set and affects the display of the table borders. It can accept any of the following parameters:

void this removes all the external borders

above this displays external borders at the top of the table only

below this displays external borders at the bottom of the table only

hsides this displays external borders at the horizontal sides of the table. ie: at the top and bottom.

lhs this displays external borders at the left hand edges of the table only

rhs this displays external borders at the right hand edges of the table only.

vsides this displays external borders at both left and right hand edges of the table

box this displays a box around the table (i.e. top, bottom, left and right hand sides)

Internet Explorer supports the RULES= command. It requires the BORDER value to be set and may only be used in tables where the <THEAD>, <TBODY> and <TFOOT> tags have been declared. It affects the display of the internal table borders ("rules"). It can accept the following parameters:

none this removes all the internal rules

basic this displays horizontal borders between the <THEAD>, <TBODY> and <TFOOT> sections

rows this displays horizontal borders between all rows

cols this displays horizontal borders between all columns

all this displays all the internal rules.

Internet Explorer provides the <COLGROUP> and </COLGROUP> tag pair which can be used within a <TABLE> definition to group columns together to set their alignment properties. It accepts the following attributes:

ALIGN="center|justify|left|right"

This sets the text alignment within the column group. The default value is "center"

VALIGN="baseline|bottom|middle|top"

This sets the vertical text alignment within the column group.

SPAN=

This can be used to set the number of columns upon which the ALIGN and VALIGN attributes are to act.

Forms:

Forms provide a mechanism for passing information from the HTML viewer back to a program at the web server or through email to you. Forms are the best way to get "true time" results or comments from your clients/viewers. We will be discussing this in depth in next (Intermediate) level of HTML.

A form is a template for a form data set and an associated method and action URI used on the WWW. Forms have no relevance to local HTML publishing. A form data set is a sequence of name/value pair fields. The names are specified on the NAME attributes of form input elements, and the values are given initial values by various forms of markup and edited by the user. The resulting form data set is used to access an information service as a function of the action and method.

Forms elements can be mixed in with document structuring elements. Example, a PRE element may contain a FORM element, or a FORM element may contain lists which contain INPUT elements. This gives considerable flexibility in designing the layout of forms.

Form Elements

<FORM>

The <FORM> element contains a sequence of input elements, along with document structuring elements. The attributes are:

ACTION= specifies the action URI for the form. The action URI of a form defaults to the base URI of the document.

METHOD= selects a method of accessing the action URI. The set of applicable methods is a function of the scheme of the action URI of the form. See section Query Forms: METHOD=GET and section Forms with Side-Effects:

METHOD=POST.

ENCTYPE = specifies the media type used to encode the name/value pairs for transport, in case the protocol does not itself impose a format.

<INPUT>

The <INPUT> element represents a field for user input. The TYPE= attribute discriminates between several variations of fields.

The <INPUT> element has a number of attributes. The set of applicable attributes depends on the value of the TYPE= attribute.

The default value of the TYPE attribute is `TEXT', indicating a single line text entry field. (Use the TEXTAREA element for multi-line text fields.)

Required attributes are:

NAME, the name for the form field corresponding to this element.

The optional attributes are MAXLENGTH which constrains the number of characters that can be entered into a text input field. If the value of MAXLENGTH is greater than the value of the SIZE attribute, the field should scroll appropriately. The default number of characters is unlimited.

SIZE specifies the amount of display space allocated to this input field according to its type. The default depends on the user agent.

VALUE defines the initial value of the field. Example:

<p>

Street Address:

Town:

Post Code:

An INPUT element with `TYPE=PASSWORD' is a text field as above, except that the value is obscured as it is entered.

Example:

<p>Name:

Password:

An INPUT element with `TYPE=CHECKBOX' represents a boolean choice. A set of such elements with the same name represents an n-of-many choice field. Required attributes are:

NAME a symbolic name for the form field corresponding to this element or group of elements.

VALUE the portion of the value of the field contributed by this element.

Optional attributes are:

CHECKED indicates that the initial state is on.

Example:

<p>

What flavours do you like?

Vanilla<br>

Strawberry<br>

Chocolate<br>

An INPUT element with `TYPE=RADIO' represents a boolean choice. A set of such elements with the same name represents a 1-of-many choice field. The NAME and VALUE attributes are required as for check boxes.

Optional attributes are:

CHECKED indicates that the initial state is on.

At all times, exactly one of the radio buttons in a set is checked. If none of the INPUT elements of a set of radio buttons specifies `CHECKED', then the user agent must check the first radio button of the set initially.

Example:

<p>

Which is your favorite?

Vanilla<br>

Strawberry<br>

Chocolate<br>

An INPUT element with `TYPE=IMAGE' specifies an image resource to display, and allows input of two form fields: the x and y coordinate of a pixel chosen from the image. The names of the fields are the name of the field with `.x' and `.y' appended. `TYPE=IMAGE' implies `TYPE=SUBMIT' processing; that is, when a pixel is chosen, the form as a whole is submitted.

The NAME attribute is required as for other input fields. The SRC attribute is required and the ALIGN is optional as for the IMG element.

Example:

<p>

Choose a point on the map:

An INPUT element with `TYPE=HIDDEN' represents a hidden field.The user does not interact with this field; instead, the VALUE attribute specifies the value of the field. The NAME and VALUE attributes are required.

Example:

An INPUT element with `TYPE=SUBMIT' represents an input option, typically a button, that instructs the user agent to submit the form.

Optional attributes are:

NAME indicates that this element contributes a form field whose value is given by the VALUE attribute. If the NAME attribute is not present, this element does not contribute a form field.

VALUE indicates a label for the input button.

Example:

You may submit this request internally:

<input type=submit name=recipient value=internal><br> or to the external world:

An INPUT element with `TYPE=RESET' represents an input option, typically a button, that instructs the user agent to reset the form's fields to their initial states. The VALUE attribute, if present, indicates a label for the input button.

Example:

When you are finished, you may submit this request:

<input type=submit><br> You may clear the form and start over at any time:

The SELECT element constrains the form field to an enumerated list of values. The values are given in OPTION elements. Attributes are:

MULTIPLE indicates that more than one option may be included in the value.

NAME specifies the name of the form field.

SIZE specifies the number of visible items. Select fields of size one are typically pop-down menus, whereas select fields with size greater than one are typically lists.

Example:

<OPTION>Vanilla

<OPTION>Strawberry

<OPTION value="RumRasin">Rum and Raisin

<OPTION selected>Peach and Orange

</SELECT>

The initial state has the first option selected, unless a SELECTED attribute is present on any of the OPTION elements.

The Option element can only occur within a Select element. It represents one choice, and has the following attributes:

SELECTED Indicates that this option is initially selected.

VALUE indicates the value to be returned if this option is chosen. The field value defaults to the content of the OPTION element.

The content of the OPTION element is presented to the user to represent the option. It is used as a returned value if the VALUE attribute is not present.

The TEXTAREA element represents a multi-line text field. Attributes are:

COLS the number of visible columns to display for the text area, in characters.

NAME specifies the name of the form field.

ROWS the number of visible rows to display for the text area, in characters.

Example:

HAL Computer Systems

1315 Dell Avenue

Campbell, California 95008

</TEXTAREA>

The content of the TEXTAREA element is the field's initial value.

Typically, the ROWS and COLS attributes determine the visible dimension of the field in characters. The field is typically rendered in a fixed-width font. HTML user agents should allow text to extend beyond these limits by scrolling as needed.

Form Submission

An HTML user agent begins processing a form by presenting the document with the fields in their initial state. The user is allowed to modify the fields, constrained by the field type etc. When the user indicates that the form should be submitted (using a submit button or image input), the form data set is processed according to its method, action URI and enctype.

When there is only one single-line text input field in a form, the user agent should accept Enter in that field as a request to submit the form.

The form-urlencoded Media Type

The default encoding for all forms is `application/x-www-form-urlencoded'. A form data set is represented in this media type as follows:

1. The form field names and values are escaped: space characters are replaced by `+', and then reserved characters are escaped as per URL; that is, non-alphanumeric characters are replaced by `%HH', a percent sign and two hexadecimal digits representing the ASCII code of the character. Line breaks, as in multi-line text field values, are represented as CR LF pairs, i.e. `%0D%0A'.

2. The fields are listed in the order they appear in the document with the name separated from the value by `=' and the pairs separated from each other by `&'. Fields with null values may be omitted. In particular, unselected radio buttons and checkboxes should not appear in the encoded data, but hidden fields with VALUE attributes present should.

Query Forms: METHOD=GET

If the processing of a form is idem potent (i.e. it has no lasting observable effect on the state of the world), then the form method should be `GET'. Many database searches have no visible side-effects and make ideal applications of query forms.

To process a form whose action URL is an HTTP URL and whose method is `GET', the user agent starts with the action URI and appends a `?' and the form data set, in `application/x-www-form-urlencoded' format as above. The user agent then traverses the link to this URI just as if it were an anchor (see section Activation of Hyperlinks).

Forms with Side-Effects: METHOD=POST

If the service associated with the processing of a form has side effects (Example, modification of a database or subscription to a service), the method should be `POST'.

To process a form whose action URL is an HTTP URL and whose method is `POST', the user agent conducts an HTTP POST transaction using the action URI, and a message body of type `application/x-www-form-urlencoded' format as above. The user agent should display the response from the HTTP POST interaction just as it would display the response from an HTTP GET above.

Example Form Submission:

<title>Sample of HTML Form Submission</title>

<H1>Sample Questionnaire</H1>

<P>

Please fill out this questionnaire:

<P>

Your name: <INPUT NAME="name" size="48">

<P>

Male <INPUT NAME="gender" TYPE=RADIO VALUE="male">

<P>

Female <INPUT NAME="gender" TYPE=RADIO VALUE="female">

<P>

Number in family: <INPUT NAME="family" TYPE=text>

<P>

Cities in which you maintain a residence:

<UL>

<LI>Miami <INPUT NAME="city" TYPE=checkbox VALUE="miami">

<LI>Other <TEXTAREA NAME="other" cols=48 rows=4></textarea>

</UL>

Nickname: <INPUT NAME="nickname" SIZE="42">

<P>

Thank you for responding to this questionnaire.

<P>

</FORM>

Note that the radio input has an initial value, while the checkbox has none.

The user might edit the fields and request that the form be submitted.

Interpretation of the message submitted is done by the URI. This requires you to have access to your WWW server and knowledge of CGI.

<title>example of forms</title>

</head>

<body>

<p>Enter Your Name:

<p>please enter your password <input type="password" name="passwd">

<p>Choose an Animal

<ul>

<li><input type="radio" name="theType" value="cat"> cat

<li><input type="radio" name="theType" value="dog">dog

<li><input type="radio" name="theType" value="fish"> fish

</ul>

Choose a vegetable.

<ul>

<li><INPUT TYPE=RADIO NAME="vegg" VALUE="tom">tomato<BR>

<li><INPUT TYPE=RADIO NAME="vegg" VALUE="zuch">zuchinni<BR>

</ul>

<p>Profession (choose all that apply):

<ul>

<li><input type="checkbox" name="doc"> Doctor

<li><input type="checkbox" name="law">Lawyer

<li><input type="checkbox" name="teacher"> Teacher

<li><input type="checkbox" name="accountant">Accountant

</ul>

<p>What is the colour of your hair?

<option value="bla"> black

<OPTION value="blo">blonde

<OPTION value="brow">brown

<option value="grey">grey

</SELECT>

<p>What is the colour of your eyes?

<option value="bla"> black

<OPTION value="blo">blonde

<OPTION selected value="brow">brown

<option value="grey">grey

</SELECT>

<p>

Comments:<br>

</textarea>

<br>

</FORM>

</body></html>

Will look like this:

Top of Form 1

Enter Your Name:

please enter your password

Choose an Animal

cat

dog

fish

Choose a vegetable.

tomato

zuchinni

Profession (choose all that apply):

Doctor

Lawyer

Teacher

Accountant

What is the colour of your hair?

What is the colour of your eyes?

Comments:

CGI-BIN

CGI stands for Common Gateway Interface which allows you to create Web pages on the fly based on information from buttons, checkboxes, text input and so on. The pages can be images, sounds, text and indeed everything else transferable by the Web. They can even be references to other Web pages.

Allows HTTP server to run programs that generate dynamic documents, rather than being restricted to delivering only static documents

To enable CGI on a Web server, Web Master designates directory as CGI-bin directory and "bin" comes from old convention that directory containing executable programs has "bin" (for BINary code) in its name -- /bin, /usr/bin, /usr/local/www/bin. Often programs named with suffix .cgi (like search.cgi) , Web server runs program and sends output from program to client.

Normally when a Web browser looks up a URL the following happens. First your computer contacts the HTTP server with the URL. The HTTP server looks at the filename requested by your computer and then sends that file back. Your computer then displays the file in the appropriate format.

However, it is possible to set up the HTTP server so that whenever a file in a certain directory is requested that file is not sent back; instead it is executed as a program, and whatever that program outputs is sent back for your computer to display. This function is called the Common Gateway Interface or CGI. The programs are called CGI scripts. The directory that the CGI scripts sit in cannot be specified by you alone - you need the help of whoever runs your HTTP server.

In summary CGI scripts are programs which can generate and send back anything: sound, pictures, HTML documents, and so on. There is a good tutorial on http://www.sanford.com/introcgi/start.html website.

Here’s a look at a CGI script. First of all, the first two lines of the print out are special. The first line must be

Content-type: text/html - so that the browser knows what kind of document it is and therefore how to display it. In this case it is a text document of the subclass HTML. You can also send back plain ASCII documents by using text/plain instead. Sound samples and images also have to have the content type specified appropriately. The second line must be blank (ie it must contain just a line feed). This line is reserved for future development.

The second point is really a tip: Strings in perl programs can span over several lines. This means the main part of your perl program can just be one enormous print statement.

For example, the following CGI Perl script:

#!/usr/local/bin/perl

# CGI script to print a basic HTML page

print "Content-type: text/html\n\n

<HEAD>

<TITLE>Simple HTML Example</TITLE>

</HEAD>

<BODY>

<HR>

<H1>Hello, this is my first CGI script!</H1>

<HR>

</BODY>

is a Perl script named cgi-bin/simple.pl. This Perl script can be called from within an HTML document with the anchored link http://www.sanford.com/introcgi/cgi-bin/simple.pl

HTML & Web Design

Advanced & Expert Levels

Day Two

Image Map

Image maps are a number of links defined as areas of a displayed image. They can be thought of as two distinct components, a map and an image. The map giving instructions as to the links and the image simply being a standard inline image. Each pixel of the image can be a link to another URL if required, but more usually different areas of

the image link to different URLs. The following example illustrates the use of a simple image map. The image is displayed as normal with an <IMG> tag, but with the addition of the USEMAP command to indicate that the inline image is an image map.

Example:

The map component may be processed by the HTML viewer (a client side image map) or by the HTTP server if the HTML viewer cannot process maps.

A server image map is defined by adding the command ISMAP to the <IMG> tag,

Example:

In this case, the HTML viewer will expect the map information to be processed by the server.

A client side image map (CSIM), however, is a map processed by the HTML viewer, which gets the map information from an HTML document found by the hyperlink following the USEMAP= command, in this case it follows later in the same document, and occurs between the <MAP> and </MAP> tags:

</MAP>

The first line tells the HTML viewer that this is a map, and assigns it a unique name, in this case "sample". The next three lines define three link areas within the image. Each area is defined with one

The forms:

These co-ordinates are pixel co-ordinates within the image and define a region within which the link occurs. The SHAPE=RECT command expects a rectangular region described by two pairs of co-ordinates. The SHAPE=CIRCLE command expects a circular region described by the co-ordinates of the circle centre, followed by the radius. The final

example, SHAPE=POLY describes a multi-sided area.

Here is the complete HTML example with blank lines inserted to make it easier to read and determine the individual areas:

<HTML>

<HEAD>

<TITLE>Example Image Map</TITLE>

</HEAD>

<BODY>

<H1 align=center>This Is An Image Map Example</H1>

</CENTER>

</MAP>

</BODY>

</HTML>

A NOHREF command, rather than an HREF= command, indicates that clicks in the defined area should not perform a hyperlink. An HREF tag specifies where a click in that area should lead. Note that a relative anchor specification will be expanded using the URL of the map description as a base, rather than using the URL of the document from which the map description is referenced (important if the map definition is in a file separate to the main document). If a BASE tag is present in the document containing the map description, that URL will be used as the base.

Any number of AREA tags may be specified within a map. If two areas intersect, the one which appears first in the map definition takes precedence in the overlapping region, and it's hyperlink jump will take place rather than the one specified in the later defined area. In this way, a default hyperlink may be made by defining an area covering the entire image, and placing this definition at the end of the map, so that any overlapping areas will take precedence over the default area.

Advanced Formatting

Multiple Spaces:

HTML viewers reduce all white space into a single space character. If you want to add spaces between words, or pad a table column with white space you can use the   entity.

Example:

Hello       World

Will display as

Hello World

Controlling Document Backgrounds

The Background Attribute

Recent versions of the proposed HTML 3.0 spec. have added a BACKGROUND attribute to the BODY tag. The purpose of this attribute is to specify a URL pointing to an image that is to be used as a background for the document. In Mosaic 2.1.1, Netscape and Internet Explorer, this background image is used to tile the full background of the document-viewing area. Thus specifying:

Document here

</BODY>

would cause whatever text, images, etc. appeared in that document to be placed on a tiled background image. If you prefer, a single large image may be displayed which does not scroll when the document window does by adding the command BGPROPERTIES=FIXED,

Example:

Document here

</BODY>

The Bgcolor Attribute

Although not standard HTML, it is possible to define the colour of the background displayed by most modern HTML viewers, including Mosaic 2.1.1, Netscape Navigator and Microsoft Internet Explorer with the BGCOLOR= command.

Document here

</BODY>

Where "#rrggbb" is a hexadecimal red-green-blue triplet used to specify the background colour.

Text Attributes

Like the BGCOLOR= command, the TEXT= command controls the attribute of normal text displayed in a document.

Document here

</BODY>

The Link, Vlink, And Alink Attribute

These attributes let you control the colouring of link text. VLINK stands for visited link, and ALINK stands for active link. The default colouring of these is: LINK=blue, VLINK=purple, and ALINK=red. Again the format for these attributes is the same as that for the BGCOLOR= and TEXT= commands.

Example:

Document here

</BODY>

Putting it all together, here is an example from Netscape which illustrates a use of global colour attributes:

<HTML>

<HEAD>

<TITLE>Colour Control Example</TITLE>

</HEAD>

<BODY BGCOLOR="#000000" TEXT="#F0F0F0" LINK="#FFFF00"

VLINK="#22AA22" ALINK="#0077FF">

This is an example document. Text is light-grey on black, and <a href="nowhere.html">anchors</a> are yellow at first, flashing blue-green when activated, and pale green if already visited.

</BODY>

</HTML>

Controlling Individual Text Attributes:

Some new HTML viewers, notably Netscape Navigator and Microsoft Internet Explorer support a new tag, <FONT>. The <FONT> tag enables the HTML author to specify a font size , colour and typeface. The size ranges from 1 to 7, smallest to largest. The colour takes a standard rgb hexadecimal triplet to define the attribute of the text within the

<FONT> and </FONT> tags.

Example:

<FONT SIZE=6 COLOR="FF0000" FACE="Arial">This is a Large Red Heading in Arial Font</FONT>

The font size can also be determined relative to the base font size using + and - in the FONT SIZE= command,

Example:

<FONT SIZE=+1>This is the next size up from the standard text</FONT>

<FONT SIZE=-1>This is the next size down from the standard text</FONT>

The base font size, colour and typeface can similarly be set with the BASEFONT command,

Example:

Will set the base font size to slightly larger than the default, which is size 3.

You can specify the name of different faces,

Example:

the HTML viewer will use "courier" if "arial" is not available on the system, or "geneva" if courier is not available either.

Preventing Line Breaks:

Both Netscape and Internet Explorer support the <NOBR> and </NOBR> tag pair which prevent a long line from being broken. Instead the document view window must be scrolled to the right by the user with the scroll-bar to view the remainder of the text line.

Example:

<NOBR>The Abecedarian were the followers of Nicholas Storck, a 16^th century German Anabaptist. They were so called because they rejected all worldly knowledge including learning the alphabet.</NOBR>

Multi-Column Text:

Currently, multi-column text only seems to be supported by Netscape Navigator. It is defined with the tag pair <MULTICOL COLS=n> and </MULTICOL>,

Example:

This is multiple column text displayed by Netscape Navigator

</MULTICOL>

Displays the text within the multicol tags in 4 columns.

The column widths and gutter between the columns can be defined by adding the WIDTH= and GUTTER= commands to the <MULTICOL> tag.

Scrolling:

Microsoft's Internet Explorer supports scrolling lines of text, which are declared by the <MARQUEE> tag. Only one line may be declared within each <MARQUEE> tag, line breaks <BR> being ignored.

Example:

This is a horizontal, animated, scrolling line of text!

</MARQUEE>

The <MARQUEE> tag also supports colour definition triplets for the background colour of the scrolling text,

Example:

This is a horizontal, animated, scrolling line of text!

</MARQUEE>

The behaviour of the scrolling text can be amended with the BEHAVIOR= command. This supports three parameters; SCROLL, SLIDE and ALTERNATE.

The default command is BEHAVIOR=SCROLL, which displays the text scrolling across the screen.

Adding the command BEHAVIOUR=ALTERNATE to the <MARQUEE> tag causes the scrolling text to scroll to the right edge of the document window, and then change direction, so that it scrolls left-to-right and then right-to-left.

The SLIDE parameter causes the text to scroll on at the right-hand side of the document window and slide over to the left before stopping, with the text displayed at the left margin of the document window.

The direction of the traveling text can be changed from right-to-left by the inclusion of the DIRECTION= command to the <MARQUEE> tag.

Example, this will scroll from left-to-right, instead of the default right-to-left.

Margins:

Microsoft's Internet Explorer supports the definition of a left and a top margin with the commands LEFTMARGIN= and TOPMARGIN= which are added to the <BODY> tag,

Example:

The margin size is measured in pixels and applies to the entire document.

Buttons:

Form buttons can be used as unusual, 3d links. Example, the following code creates a 3d button with the inscription "Link", which when pressed jumps to the URL

www.pins.co.uk/upages/probertm/index.html.

Inline Video:

Microsoft's Internet Explorer allows the author to embed .AVI (Audio Video Interleave) video clips in HTML documents. This is done with the DYNSRC= command for the <IMG> tag. Using the <IMG> tag for this purpose makes it possible to add video clips to pages, but also have other browsers display still images in their place.

Example;

<IMG DYNSRC="video.avi" SRC="dancing.gif" WIDTH=50 HEIGHT=50

LOOP=INFINITE ALIGN=RIGHT>

The DYNSRC= command specifies the address of a video clip to be displayed in the window. In the above example, Internet Explorer will play the movie file "video.avi"; while other browsers will display the picture "dancing.gif"

You can add a START= command to the tag to specify when the video file should start playing. This attribute can be set to either FILEOPEN or MOUSEOVER. The default setting is FILEOPEN which means that the video will start playing as soon as the HTML document has finished loading. The MOUSEOVER parameter defines that the video will start playing when the user moves the mouse cursor over the animation. Both can be specified together if necessary.

The CONTROLS command is a flag, which if specified causes a set of controls to be displayed under the video clip window.

The LOOP= command specifies how many times a video clip will loop when activated. If n=-1, or if LOOP=INFINITE is specified, the video will loop indefinitely.

The LOOPDELAY= command specifies, in milliseconds, how long a video clip will wait between play back loops.

Embedded Objects:

The <EMBED> tag allows you to put objects (video clips, sound or whatever) directly into an HTML page. The syntax is:

The <EMBED> element allows an HTML author to embed documents of any type. The HTML viewer needs to have an application which can view the data installed correctly on their machine, or have a "plug-in" (for Netscape Navigator) that can manipulate the embedded file format.

The <EMBED> element can be used more or less the same as the <IMG> element and so accepts typical image embedding commands such as WIDTH, HEIGHT, BORDER, HSPACE, VSPACE.

Example, to embed a sound file:

Which are then downloaded to the HTML viewer, and played by a fitted soundcard, if the user has one and the HTML viewer supports sound.

Frames

Frames divide Web pages into multiple, scrollable regions which enable the HTML author to present information in a more flexible and useful fashion. Each region, or frame, has several features:

1. It can be given an individual URL, so it can load information independent of the other frames on the page;

2. It can be given a NAME, allowing it to be targeted by other URLs, and;

3. It can resize dynamically if the user changes the window's size.

(Resizing can also be disabled, ensuring a constant frame size.)

A frame is declared with the start-tag <FRAMESET> and the end-tag </FRAMESET> which replace the traditional <BODY> and </BODY> tags in a standard HTML document. The FRAMESET start-tag defines how many frames (regions) the viewer window will be divided into, and the sizes of these regions. The region sizes are defined in terms of pixel rows and columns. Example, to divide the document window into two equal frames, one above the other you can use the command;

The ROWS= command takes a comma separated list of pixel heights in numbers, or in percentages or * to declare the pixel row height of each frame. Replacing a number with an asterisk * tells the HTML viewer to divide the available display area equally. The COLS= command is similar, but applies to the horizontal width of each frame.

This example will split the display into two equal windows, and display a different URL in each, 1.htm in one and 2.htm in the other:

<html>

<head>

<title>Frame Example</title>

</head>

</frameset>

</html>

This example does the same, but divides the display vertically instead of horizontally;

<html>

<head>

<title>Frame Example</title>

</head>

</frameset>

</html&g