Conditional Comments are the name of HTML style comments that contain conditional directives for the browser. They are for IE only and thus are often employed in dealing with IE only CSS bugs like so:
<!--[if lt IE 7]>
<style type="text/css" media="all">
@import url(http://example.com/IEFixes.css);
</style>
<![endif]-->
This article gives good examples and provides a link to the official Microsoft document.
Posted by dante at November 17, 2006 10:54 AM