var request = null;
try {
  request = new XMLHttpRequest();
} catch (trymicrosoft) {
  try {
    request = new ActiveXObject("Msxml2.XMLHTTP");
  } catch (othermicrosoft) {
    try {
      request = new ActiveXObject("Microsoft.XMLHTTP");
    } catch (failed) {
      request = null;
    }
  }
}

if (request == null)
  alert("Error creating request object!");

function get_request(){
  var request = null;
  try {
    request = new ActiveXObject("Msxml2.XMLHTTP");
  } catch (e) {
    try {
      request = new ActiveXObject("Microsoft.XMLHTTP");
    } catch (E) {
      request = false;
    }
  }
  if (!request && typeof XMLHttpRequest!='undefined') {
    request = new XMLHttpRequest();
  }
  return request;
}