function demoPopup(prefix) {
        var w = 750;
        var h = 550;
        var winl = (screen.width - w) / 2;
        var wint = (screen.height - h) / 2;
        //var url = prefix + '/flash/demo/popup.html';
        var url = 'http://lb.img.app.pbnext.com/engine/pbnext.com/demo/popup.html';
        var args = 'location=no, menubar=no, resizable=no, scrollbars=no, status=no, toolbar=no';
        window.open(url,'demoWin',args+',width='+w+',height='+h+',left='+winl+',top='+wint);
      }