var xhReq;    
    function createXMLHttpRequest() {
        try { return new ActiveXObject("Msxml2.XMLHTTP"); } catch (e) {}
        try { return new ActiveXObject("Microsoft.XMLHTTP"); } catch (e) {}
        try { return new XMLHttpRequest(); } catch(e) {}
        alert("XMLHttpRequest not supported");
        return null;
    }

    function ExecuteA( page, vars, callBack){
        xhReq = createXMLHttpRequest();
        xhReq.open( "POST" , page, true);
        xhReq.setRequestHeader("Content-Type", "application/x-www-form-urlencoded; charset=UTF-8");
        xhReq.send(vars);
        xhReq.onreadystatechange = callBack;
    }