if (/MSIE (\d+\.\d+);/.test(navigator.userAgent)){ //test for MSIE x.x;
 var ieversion=new Number(RegExp.$1) // capture x.x portion and store as a number
 if (ieversion>=6)
  document.write('<link rel="stylesheet" href="/css/ie6exception.css" type="text/css" />')
 else if (ieversion>=5)
  document.write('<link rel="stylesheet" href="/css/ie6exception.css" type="text/css" />')
}
else
 document.write('<link rel="stylesheet" href="/css/MozStylesheet.css" type="text/css" />')