xhr ทำให้เวลาใช้งานใน IE 9 ลงมา ไม่ทำงาน รบกวนขอวิธีแก้ไขหน่อยครับ

var ele_alert;
function ajax_GET(url, parameters, ele) {
	ele_alert = ele;
	http_request = false;
	if (window.XMLHttpRequest) { //Moszila
		 http_request = new XMLHttpRequest();
		 if (http_request.overrideMimeType) { http_request.overrideMimeType('text/html'); }
	} else if (window.ActiveXObject) { // IE
		 try { http_request = new ActiveXObject("Msxml2.XMLHTTP");
		 } catch (e) { try { http_request = new ActiveXObject("Microsoft.XMLHTTP"); } catch (e) {} }
	}
	if (!http_request) { alert('Cannot create XMLHTTP instance'); return false; }
	http_request.onreadystatechange = alertContents;
	http_request.open('GET', url, true);
	http_request.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
	http_request.setRequestHeader("Content-length", parameters.length);
	http_request.setRequestHeader("Connection", "close");
	http_request.send(parameters);
}
function alertContents() {
	if (http_request.readyState == 4) {
		if (http_request.status == 200) {
			request_ok( http_request.responseText);
		} else { alert('There was a problem with the request.'+http_request.status);}
	}
}
function requst_ok( rs){
    alert(rs);
    if(ele_alert == 'test') run_this();
    else run_that();
}
function run_this(){

}
function run_that(){

}

var url = 'http://myweb.com';
var parameter = 'data=xxbbbcccddd&id=100';
ajax_GET(url, parameters, 'test');

xhr: function(){
	var xhr = new window.ActiveXObject;
	//Upload progress
	xhr.upload.addEventListener("progress", function(evt){
		if (evt.lengthComputable) {
			var percentComplete = evt.loaded / evt.total;
			l.setProgress( percentComplete );
		}
	}, false);
	return xhr;
}