JS监听浏览器刷新、关闭事件

var UnloadConfirm = {};
UnloadConfirm.MSG_UNLOAD = "数据尚未保存，离开后可能会导致数据丢失\n\n您确定要离开吗？";
UnloadConfirm.set = function(a) {
    window.onbeforeunload = function(b) {
        b = b || window.event;
        b.returnValue = a;
        return a
    }
};
UnloadConfirm.clear = function() {
    fckDraft.delDraftById();
    window.onbeforeunload = function() {}
};
UnloadConfirm.set(UnloadConfirm.MSG_UNLOAD);
js 阻止浏览器刷新 关闭、js监听浏览 关闭 刷新 兼容IE6+ Firefox Chrome Safari