网页屏蔽各种按键的代码分享

<script>
//屏蔽鼠标右键、Ctrl+N、Shift+F10、F11、F5刷新、退格键
    function document.oncontextmenu(){event.returnValue=false;}
//屏蔽鼠标右键
    function window.onhelp(){return false} 
//屏蔽F1帮助 
    function document.onkeydown(){ if((window.event.altKey)&&((window.event.keyCode==37)|| 
//屏蔽Alt+方向键← 
    (window.event.keyCode==39))){ 
//屏蔽Alt+方向键→ 
    alert("不准你使用ALT+方向键前进或后退网页！"); event.returnValue=false; } 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; } if(event.keyCode==122){event.keyCode=0;event.returnValue=false;} 
//屏蔽F11 
    if(event.ctrlKey && event.keyCode==78)event.returnValue=false; 
//屏蔽Ctrl+n 
    if(event.shiftKey && event.keyCode==121)event.returnValue=false; 
//屏蔽shift+F10 
    if(window.event.srcElement.tagName=="A" && window.event.shiftKey) window.event.returnValue=false; 
//屏蔽shift加鼠标左键新开一网页
    if((window.event.altKey)&&(window.event.keyCode==115)){ 
//屏蔽Alt+F4
    window.showModelessDialog("about:blank","","dialogWidth:1px;dialogheight:1px"); return false; } } 
</script>