JS 禁止浏览器右键菜单和刷新

 <script language="javascript">
 //禁止按键F5
 document.onkeydown = function(e){
     e = window.event || e;
     var keycode = e.keyCode || e.which;
     if( keycode = 116){
         if(window.event){// ie
             try{e.keyCode = 0;}catch(e){}
             e.returnValue = false;
         }else{// ff
             e.preventDefault();
         }
     }
 }

 //禁止鼠标右键菜单
 document.oncontextmenu = function(e){
          return false;
 }
 </script>