// setActiveStyleSheet changes css file for IE
function setActiveStyleSheet() {
   var title="ie_style";
   var i, a, main;
   for(i=0; (a = document.getElementsByTagName("link")[i]); i++) {
     if(a.getAttribute("rel").indexOf("style") != -1
        && a.getAttribute("title")) {
       a.disabled = true;
       if(a.getAttribute("title") == title) a.disabled = false;
     }
   }
}

function checkBrowser() {
  var agt=navigator.userAgent.toLowerCase();
  var is_major = parseInt(navigator.appVersion);
  var is_ie     = ((agt.indexOf("msie") != -1) && (agt.indexOf("opera") == -1));
  var is_ie4up  = (is_ie && (is_major >= 4));
  if (is_ie4up) setActiveStyleSheet(); 
}