function makeRequest(url) {
    var httpRequest;

    if (window.XMLHttpRequest) {
        httpRequest = new XMLHttpRequest();
        if (httpRequest.overrideMimeType) {
            httpRequest.overrideMimeType('text/xml');
        }
    }
    else if (window.ActiveXObject) {
        try {
            httpRequest = new ActiveXObject("Msxml2.XMLHTTP");
            }
            catch (e) {
                       try {
                            httpRequest = new ActiveXObject("Microsoft.XMLHTTP");
                           }
                         catch (e) {}
                      }
                                   }

    if (!httpRequest) {
        alert('Giving up :( Cannot create an XMLHTTP instance');
        return false;
    }
    httpRequest.onreadystatechange = function() { ajaxAction(httpRequest); };
    httpRequest.open('POST', url, true);
    httpRequest.send(null);

}