The Highlighter

This is highlighting in Internet Explorer. It uses the stuff on line 9; p{behavior: url(hl.htc);}, as well as the hl.htc file.

This is highlighting in Mozilla FireFox, aka Netscape, AOL, Firefox... It uses the stuff on line 10; a:hover{color: red;}. It does not need to reference hl.htc, you just need to have line 10 inside the style tags and <a>, </a> tags.

And this is not highlighted.

So you should use both to make sure everyone sees it!