function screenSize() {
      var w, h;
      w = (window.innerWidth ? window.innerWidth : (document.documentElement.clientWidth ? document.documentElement.clientWidth : document.body.offsetWidth));
      h = (window.innerHeight ? window.innerHeight : (document.documentElement.clientHeight ? document.documentElement.clientHeight : document.body.offsetHeight));
      return {w:w, h:h};
}