function createXMLHttpRequest() {

var ua;

if(window.XMLHttpRequest) {
    try {
      ua = new XMLHttpRequest();
    } catch(e) {
      ua = false;
    }
  } else if(window.ActiveXObject) {
    try {
      ua = new ActiveXObject("Microsoft.XMLHTTP");
    } catch(e) {
      ua = false;
    }
  }
  return ua;
}