常用的JS屏蔽相关键盘操作

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=0;
       //event.returnValue=false; //注释此句是禁止网页后退,但可以执行删除数据
}

if ((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;
}
}