Inserire loader durante chiamata ajax

[carlomarx]

var xmlhttpPost = (function () {

    function reqListener () {
        alert(this.responseText);
        oWait.parentNode && oWait.parentNode.removeChild(oWait);
    }

    function reqError (oEvent) {
        alert("C\'\u00E8 stato un errore durante la chiamata AJAX.");
        oWait.parentNode && oWait.parentNode.removeChild(oWait);
    }

    var oWait = document.createElement("div");

    /* "oWait" e' un div... ci puoi mettere dentro tutto quello che ti pare... */
    oWait.appendChild(document.createTextNode("Attendi..."));

    return function (sURL) {
        var oReq = new XMLHttpRequest();
        oReq.onload = reqListener;
        oReq.onerror = reqError;
        oReq.open("GET", sURL, true);
        oReq.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
        oReq.send(recuperaValore());
        oWait.parentNode || document.body.appendChild(oWait);

    };

})();