javascript通用添加、删除事件监听方法函数

        function addEvent(obj, type, fn) {
            if (obj.attachEvent) {
                obj['e' + type + fn] = fn;
                obj[type + fn] = function () { obj['e' + type + fn](window.event); }
                obj.attachEvent('on' + type, obj[type + fn]);
            } else
                obj.addEventListener(type, fn, false);
        }
        function removeEvent(obj, type, fn) {
            if (obj.detachEvent) {
                obj.detachEvent('on' + type, obj[type + fn]);
                obj[type + fn] = null;
            } else
                obj.removeEventListener(type, fn, false);
        }