js页面的全屏展示和退出全屏显示

 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
 <HTML>
     <HEAD>
     <TITLE> New Document </TITLE>
     <SCRIPT LANGUAGE="javascript">
         <!-- Begin KeyDown
         function showKeyDown(evt) {
             evt = (evt) ? evt : window.event;
             if (evt.keyCode == 27) {
                 window.close(self);
             }
         }
         // End -->
         <!-- Begin onClick
         if (this.name!='fullscreen'){
             window.open(location.href,'fullscreen','fullscreen,scrollbars');
         }
         // End -->
     </script>
     </HEAD>
     <BODY  onLoad="document.onkeydown = showKeyDown">
         <a onClick="window.close(self)">返回正常效果显示</a>
     </BODY>
 </HTML>