屏蔽鼠标右键 F5 退格键， CTRL+R

<script type="text/javascript"> 

function document.oncontextmenu(){event.returnValue=false;}//屏蔽鼠标右键 


function document.onkeydown() 

{ 

 if ((event.keyCode==8) || //屏蔽退格删除键 

 (event.keyCode==116)|| //屏蔽 F5 刷新键 

 (event.ctrlKey && event.keyCode==82)){ //Ctrl + R 

 event.keyCode=0; 

 event.returnValue=false; 

 } 


} 

</script>