function getWindowSize(mode) {
   var win = window;
   var d = document;
   var w = win.innerWidth || d.documentElement.clientWidth || d.body.clientWidth || 0;
   var h = win.innerHeight || d.documentElement.clientHeight || d.body.clientHeight || 0;
   return (mode == 'w') ? w : (mode == 'h') ? h : { width: w, height: h };
}