怎样锁右键，和解开右键？

锁右键：

<script language="javascript">

function Curdate()

{

var today=new Date();

yearStr=1900+today.getYear();

monthStr=today.getMonth()+1;

dateStr=today.getDate();

weekVal=today.getDay();

msg="每日综述（"+yearStr+"年"+monthStr+"月"+

""+dateStr+"日）"

return msg;

}

function click() {

if (event.button==2) {

alert("中国黄沙果园信息网！欢迎您的到来！")

}

}

document.onmousedown=click

</script>

解开右键：先按左健不动,按下右健,放开左健,放开右健,就可以看到原来的菜单，用shift＋F10也可以