We recall that a link in HTML is always composed of two parts, the clickable part (the link text) and the URL (Uniform Resource Locator, the destination site, page or resource). Here is an example:
Clickable part (link text): PHP-Nuke HOWTO.
The HTML code for this link is:
<a href="http://www.karakas-online.de/EN-Book/">PHP-Nuke HOWTO</a>
which will look like: PHP-Nuke HOWTO. As you can see, the <a> tag is closed with </a>.
Some rules for creating links:
If the link points to an external site, the address must always start with "http://".
If the link points to an internal page in the same directory as the page setting the link, it suffices to give only the name of the file. This will be a little faster, as we save a DNS query on the site's fully quallified domain name. It also saves you administration headaches, should you choose to move your files under a different directory: in case of absolute paths, you would have to change all of them in your code. Finally, if you use relative paths, you can still navigate around your pages locally, on your development server, without having to upload all files on the web server first. See also Relative vs. Absolute Links and About Paths.
We can pass parameters (the so-called "URL parameters") on the link. PHP-Nuke make heavy use of this feature: all PHP-Nuke modules are called through a link that passes the module's name to the modules.php script, as in the following example for the News module:
The link text can be treated just as any other text in HTML, assigning it colour and size, in the same way as we do it for normal text (see Section 28.2.1).