禁止左右键代码

禁止鼠标左右键，代码加入HEAD标签，本页已加入演示

<SCRIPT LANGUAGE=javascript>
function click() {
alert('NO') }
function click1() {
if (event.button==2) {alert('NO') }}
function CtrlKeyDown(){
if (event.ctrlKey) {alert('NO') }}
document.onkeydown=CtrlKeyDown;
document.onselectstart=click;
document.onmousedown=click1;
</SCRIPT>