js判斷瀏覽器載入對應CSS

<script language="javascript">
if(window.navigator.userAgent.indexOf("MSIE 6.0")>=1){
  //如果瀏覽器為IE
  setActiveStyleSheet("style1.css");
}
else if(window.navigator.userAgent.indexOf("MSIE 7.0")>=1){
  //如果瀏覽器為Firefox
  setActiveStyleSheet("style2.css");
}
else if(window.navigator.userAgent.indexOf("Firefox")>=1){
  //如果瀏覽器為Firefox
  setActiveStyleSheet("style3.css");
}
else{
  //如果瀏覽器為其它
  setActiveStyleSheet("style4.css");
}

function setActiveStyleSheet(filename){
 
   document.write("<link href=/"//css//"+filename+"/" type=/"text//css/" rel=/"stylesheet/">");

}
</script>