function post_ajax(object, msg) {

    var ret = "test !";
    // création de l'objet AJAX
    if (window.XMLHttpRequest) // Firefox
        xhr_object = new XMLHttpRequest();
    else {
        if (window.ActiveXObject) // IE
            xhr_object = new ActiveXObject("Microsoft.XMLHTTP");
        else
            return (false);
    }

    xhr_object.open("POST", "mail.php", false);
    xhr_object.setRequestHeader("Content-Type", "application/x-www-form-urlencoded;");
    xhr_object.send("object=" + object + "&msg=" + msg);

    if (xhr_object.status == 200) {
        ret = "OK";
    }
    else {
        //alert("Erreur AJAX\nError code : " + xhr_object.status);
        ret = "an error as occured, please contact an administrator !\n(error no " + xhr_object.status + ")";
    }

    return ret;

}