var http = getHTTPObject(); // Creamos el objeto XMLHttpRequest

//INICIO-----------------------------------------------
function StarConax(url,cadena,asc){
        var ahora = new Date();
        http.open('POST', url, asc);
        http.setRequestHeader('Content-Type','application/x-www-form-urlencoded');
        http.onreadystatechange = handleHttpResponse;
        http.send(cadena + '&ttmr?' + ahora);
}
//MONITOR DE ESTADO------------------------------------
function handleHttpResponse() {
       if (http.readyState == 4 && http.status == 200) { 
          ResultConax(http.responseText);
       }

}

//CREACION DEL OBJETO HTTP-----------------------------
function getHTTPObject() { 
var xmlhttp; 
        if (window.XMLHttpRequest) { // Mozilla, Safari,...
            xmlhttp = new XMLHttpRequest();
          //  xmlhttp.overrideMimeType('text/xml');
            if (xmlhttp.overrideMimeType) {
                xmlhttp.overrideMimeType('text/xml');
            }
        } else if (window.ActiveXObject) { // IE
            try {
                xmlhttp = new ActiveXObject("Msxml2.XMLHTTP");
            } catch (e) {
                try {
                    xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
                } catch (e) {}
            }
        }
        if (!xmlhttp) {
            alert('Falla :( No es posible crear una instancia XMLHTTP');
            return false;
        }
return xmlhttp; 
}