function InitXmlHttp() {
    // Attempt to initialize xmlhttp object
    try {
        xmlhttp = new ActiveXObject("Msxml2.XMLHTTP");
    }
    catch (e) {
        // Try to use different activex object
        try {
            xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
        }
        catch (E) {
            xmlhttp = false;
        }
    }

    // If not initialized, create XMLHttpRequest object
    if (!xmlhttp && typeof XMLHttpRequest != 'undefined') {
        xmlhttp = new XMLHttpRequest();
    }
    // Define function call for when Request obj state has changed
    xmlhttp.onreadystatechange = XMLHttpRequestCompleted;
}

function InvokeAshx(url)
{
    InitXmlHttp();
    xmlhttp.onreadystatechange = XMLHttpRequestCompleted;
    xmlhttp.open("GET", "" + url, true );
    xmlhttp.send(null);
}

function XMLHttpRequestCompleted()
{
    if (xmlhttp.readyState == 4) {
        try {
            eval(xmlhttp.responseText);
        }
        catch (e) {
            alert(e);
        }
    }
}