js屏蔽F5 兼容ie和firefox

<script type="text/javascript">
    //禁止用F5键(兼容IE和Firefox)  
    var check = function(e) {
        e = e || window.event;
        if ((e.which || e.keyCode) == 116 || (e.ctrlKey && (e.which || e.keyCode) == 82)) {
            if (e.preventDefault) {
                e.preventDefault();
            }
            else {
                event.keyCode = 0;
                e.returnValue = false;
            }
        }
    }
    if (document.addEventListener) {
        document.addEventListener("keydown", check, false);
    }
    else {
        document.attachEvent("onkeydown", check);
    }
</script>