// get browser: Internet Explorer or other
 var isExplorer = (navigator.appVersion.indexOf("MSIE") != -1) ? true : false;
 var isNav6 =  (!isExplorer) && (navigator.appVersion.charAt(0) > "4")
 
// get platform: Mac or other
 if (top.navigator.platform != null) {
  // get browser platform
  this.platform = navigator.platform;
 } else {
  // get platform for browsers that don't support navigator.platform
  var startindex = navigator.appVersion.indexOf("(") + 1;
  var endindex = navigator.appVersion.indexOf(";");
  this.platform = navigator.appVersion.substring(startindex,endindex);
 }
 var isMac = (this.platform.indexOf("Mac") != -1) ? true : false;
 var isWindows = (navigator.appVersion.indexOf("Windows") != -1) ? true : false;
 
// select stylesheets based on browser and platform
 if (isMac) {
  if (isExplorer) {
   document.write ("<LINK REL='stylesheet' HREF='prv.css' TYPE='text/css'>");
  }else if (isNav6) {
   document.write ("<LINK REL='stylesheet' HREF='prv.css' TYPE='text/css'>"); 
  } else {
   document.write ("<LINK REL='stylesheet' HREF='prv-ns.css' TYPE='text/css'>");
  }
 } else {
  if (isExplorer) {
   document.write ("<LINK REL='stylesheet' HREF='prv.css' TYPE='text/css'>");
  }else if (isNav6) {
   document.write ("<LINK REL='stylesheet' HREF='prv.css' TYPE='text/css'>"); 
  } else {
   document.write ("<LINK REL='stylesheet' HREF='prv-ns.css' TYPE='text/css'>");
  }
 }
 
function LogOut() {
	ht=document.getElementsByTagName("body");
	ht[0].style.filter="progid:DXImageTransform.Microsoft.BasicImage(grayscale=1)";
	if (confirm('WARNING!\nAre you sure you want to logoff?')) {
		return true;
	} else {
		ht[0].style.filter="";
		return false;
	}
 }