JS屏蔽F5

目录：

概述：

JS如何屏蔽F5：

    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;
        }
    }