createXMLHttpRequest很好的一段代码

var aj = new Object();

 

aj.createXMLHttpRequest = function() {
  var request = false;
  if(window.XMLHttpRequest) {
   request = new XMLHttpRequest();
   if(request.overrideMimeType) {
    request.overrideMimeType('text/xml');
   }
  } else if(window.ActiveXObject) {
   var versions = ['Microsoft.XMLHTTP', 'MSXML.XMLHTTP', 'Microsoft.XMLHTTP', 'Msxml2.XMLHTTP.7.0', 'Msxml2.XMLHTTP.6.0', 'Msxml2.XMLHTTP.5.0', 'Msxml2.XMLHTTP.4.0', 'MSXML2.XMLHTTP.3.0', 'MSXML2.XMLHTTP'];
   for(var i=0; i    try {
     request = new ActiveXObject(versions[i]);
     if(request) {
      return request;
     }
    } catch(e) {}
   }
  }
  return request;
 }