HTML (HyperText Markup Language) is used to write the material you have been viewing on the Web. It is a SGML-based markup langauge (SGML= Standard Generalized Markup Language. See ISO 8879).
From an earlier discussion, we mentioned that word processing is done either with a WYSIWYG word processor or a markup language. Web documents fit into the latter category.
A markup language is much like a miniature program. It gives explicit instruction in an established syntax to a machine (in this case the machine is your browser) to display information in certain ways. As an example of HTML code, consider the following.
<html>
<head>
</head>
<body>
This is the text in my HTML document.
</body>
</html>
When formatted you see this.
HTML supports a limited number of formatting options. That makes it relatively easy to learn but limits the looks of the documents you can create. Each Web browser client is responsible for handling the HTML markup language tags correctly. Although there are standards, web brower developers are always pushing the boundaries of the technology past the standards. Thus implementations of tags, especially newer tags will differ among web browsers, and what looks good when viewed with one web browser may not look as nice or the same on another.
<head> <title>HTML Introduction</title> </head>
When formatted you see this. Notice all this does is title the window.
The six heading tags look like this. Remember the WWW client determines how they will look on your machine.
The ol or ul tag starts the list. The actual list items each have their own li tag. The list is terminated with the /ol or /ul tag.
<ol> <li>This is item one. <li>This is item two. </ol>
An ordered list looks like this.
A bulletted list looks like this.
Here is a sample definition list.
<dl>
<dt>WWW
<dd>The World Wide Web
<dt>Netscape, Internet Explorer, Mosaic
<dd>World Wide Web browsers
</dl>
These may be combined, but cannot be overlapped.
Images are added to a document with the img tag, (like the U.S. icon at the right). It is a little more complicated than the text tags we have discussed so far.
<img align=top src="name_of_image_file.gif" alt="no picture">
<a href="http://machine/directory/file.html">
followed by text that is clickable
</a>
Here is an example.
These links are not limited to text. Gopher or ftp could replace the http above and that type of connection would then be made.
Note that while HTML tags are case insensitive many server operating systems are not, (e.g., UNIX, Mac OS, etc.). Thus file names embedded in links should be identical to the file name as it will be stored on the WWW server machine.
Anchor links are intra-document hyper-links within the same document on the WWW. These are also created with the a and the /a tag pair.
<a href="#anchorName">
followed by text that is clickable
</a>
The named anchor must be created in the current document using the name option of the a /a tag.
<a name="anchorName"> followed by the anchor text that the anchor links to </a>
Here is a sample table
|
Column 1 Heading |
Column 2 Heading |
|---|---|
|
Cell 1,1 |
Cell 1,2 |
|
Cell 2,1 |
Cell 2,2 |
|
Cell 3,1 |
|
|
Cell ?? |
|
and the HTML that created it.
<TABLE border>
<CAPTION> My Table Caption </CAPTION>
<TR>
<TH> Column 1 Heading</TH>
<TH> Column 2 Heading</TH>
</TR>
<TR>
<TD> Cell 1,1 </TD>
<TD> Cell 1,2 </TD>
</TR>
<TR>
<TD ALIGN=CENTER> Cell 2,1 </TD>
<TD ALIGN=RIGHT> Cell 2,2 </TD>
</TR>
<TR>
<TD > Cell 3,1 </TD>
</TR>
<TR>
<TD COLSPAN=2> Cell ?? </TD>
</TR>
</TABLE>
|
HTML and Netscape |
|---|
There are many features of HTML not mentioned above. Most WWW clients provide a way for you to download a WWW document with the HTML tags. Find a few pages you think look good, download the document with tags, and see what tags were used.
Explore these references for more information.