if (navigator.userAgent.indexOf("MSIE") != -1) {
	document.write('<link rel="STYLESHEET" href="ie.css" type="text/css">');
}
else if (navigator.userAgent.indexOf("Firefox") != -1) {
	document.write('<link rel="STYLESHEET" href="ff.css" type="text/css">');
}
else {
	document.write('<link rel="STYLESHEET" href="other.css" type="text/css">');
}