function GetXmlHttpObject()
{
  var xmlHttp=null;
  try
    {
    // Firefox, Opera 8.0+, Safari
    xmlHttp=new XMLHttpRequest();
    }
  catch (e)
    {
    // Internet Explorer
    try
      {
      xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");
      }
    catch (e)
      {
      xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
      }
    }
  return xmlHttp;
}
function addEvent(elm, evType, fn, useCapture){
	if (elm.addEventListener)
	{
		elm.addEventListener(evType, fn, useCapture);
		return true;
	} 
	else if (elm.attachEvent) 
	{
		 var r = elm.attachEvent('on' + evType, fn);
		 return r;
	} 
	else 
	{
		elm['on' + evType] = fn;
	}
}