function ShowProgressBar(progressBar, progressValue, message) {
            progressBar.show();
            progressBar.updateProgress(progressValue, message);
//need to add the css class here something like progressBar.addClass('green-bar')
        }

.green-bar{
        background:#008000;
}

listeners: {
    update: function (obj, val) {
        obj.getElelement().child("PROGRESSBAR_NAME", true).style.backgroundColor = "#FF00CC";
    }
}

.green-bar .x-progress-bar{
        background:#008000;
}

progressBar.addClass('green-bar'); //obviously i have removed the added css class after use.