屏蔽页面快捷键

<script language="Javascript">
<!--
function KeyDown(){
if ((window.event.altKey)&&
((window.event.keyCode==37)|| //屏蔽 Alt+ 方向键 ←www.yanet.cn
(window.event.keyCode==39))){ //屏蔽 Alt+ 方向键 →
alert("^_^");
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.ctrlKey)&&(event.keyCode==78)) //屏蔽 Ctrl+n
event.returnValue=false;
if ((event.shiftKey)&&(event.keyCode==121)) //屏蔽 shift+F10
event.returnValue=false;
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("http://www.baofeng.gov.cn","","dialogWidth:1px;dialogheight:1px");
return false;}
}

// -->
</script>