This is in response to Bazz's post. I wrote it on another forum, but it is the same thing:
IE is known to have issues, and many sites are built around it. However, sometimes a site will be incorrectly coded, but IE will display it anyways. (IE is NOT W3C compliant)
Markup is the HTML code and tags (HTML=Hypertext Markup Language).
The W3C is the World Wide Web Consortium, and is the governing body on web standards. They set what is and isn't allowed in code. Web browsers are based, among others, on how well they conform to W3C Standards. This is done so that every browser that is W3C compliant will show pages exactly the same, hence IEs problem.
Your code can also be validated for errors. The errors come from a DTD, or Document Type Definition, which says what is and isn't allowed in the code. I noticed you were coding in XHTML 1.0 Strict. This DocType is somewhat different from regular HTML like you have been using, as many tags and attributes are depreciated. The rules are different, and many tags are no longer legal.
The link given to you by Bazz http://validator.w3.org/check?verbos..._test_run.html
is W3Cs validator.
It shows you errors on the page. Fix those errors, than work on getting the site right. One tip: Do NOT build the site for IE as IE is, as I set, NOT W3C compliant. Build it for Firefox or Safari and than work out the kinks in IE. It will be much easier that way.
(Programs like Dreamweaver have tools built in to verify if a site is compliant with a browser, as well as the W3C.)
Hope this helped.