js禁止页面使用右键(简单示例代码)

function click(e) {
if (document.all) {
if (event.button==1||event.button==2||event.button==3) {
oncontextmenu=return false;
}
}
if (document.layers) {
if (e.which == 3) {
oncontextmenu=return false;
}
}
}
if (document.layers) {
document.captureEvents(Event.MOUSEDOWN);
}
document.onmousedown=click;
document.oncontextmenu = new Function("return false;")