var xmlhttp;
function CallAjax(url) {
    xmlhttp = GetXmlHttpObject();
    if (xmlhttp == null) {
        alert("Your browser does not support XMLHTTP!");
        return;
    }
    xmlhttp.onreadystatechange = stateChanged;
    xmlhttp.open("GET", url, true);
    xmlhttp.send(null);
}

function stateChanged() {
    if (xmlhttp.readyState == 4) {
        var result=xmlhttp.responseText;
    }
}
 function GetXmlHttpObject() {
        if (window.XMLHttpRequest) {
            // code for IE7+, Firefox, Chrome, Opera, Safari
            return new XMLHttpRequest();
        }
        if (window.ActiveXObject) {
            // code for IE6, IE5
            return new ActiveXObject("Microsoft.XMLHTTP");
        }
        return null;
    }