function ajaxFunction() {
    var xmlHttp;
    try {    // Firefox, Opera 8.0+, Safari
        xmlHttp=new XMLHttpRequest();
    }
    catch (e) {    // Internet Explorer
        try {
            xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");
        }
        catch (e) {
            try {
                xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
            }
            catch (e){
                return false;
            }
        }
    }
    return xmlHttp;
}