function createXMLHttpRequest(){ 
  // See http://en.wikipedia.org/wiki/XMLHttpRequest 
  // Provide the XMLHttpRequest class for IE 5.x-6.x: 
  if( typeof XMLHttpRequest == "undefined" ) XMLHttpRequest = function() { 
    try { return new ActiveXObject("Msxml2.XMLHTTP.6.0") } catch(e) {} 
    try { return new ActiveXObject("Msxml2.XMLHTTP.3.0") } catch(e) {} 
    try { return new ActiveXObject("Msxml2.XMLHTTP") } catch(e) {} 
    try { return new ActiveXObject("Microsoft.XMLHTTP") } catch(e) {} 
    throw new Error( "This browser does not support XMLHttpRequest." ) 
  }; 
  return new XMLHttpRequest(); 
}