Problem loading different stylesheets for different browsers

Hi all

Im trying to load different stylesheets for different browsers.
I’ve tryed using

<!--[if lte IE 6]>
<link rel="stylesheet" type="text/css" href=style_IE.css">
<![endif]-->

without success in my (header.php)

It just ignore that code snippet. I’ve also tryed jusing javascript to detect different browsers, but still no succsess.
Hopefully together we can solve this error. Have a nice day