JS禁止页面刷新

<script type="text/javascript">document.onkeydown = function (e) {var ev = window.event || e;var code = ev.keyCode || ev.which;if (code == 116) {ev.keyCode ? ev.keyCode = 0 : ev.which = 0;cancelBubble = true;return false;}} //禁止f5刷新document.οncοntextmenu=function(){return false};//禁止右键刷新</script>