自定义事件

window.onload = function() {
    var div1 = document.getElementById('div1');
    var div2 = document.getElementById('div2');
    addEvent(div1, 'click', function() {
        alert(1);
    });
    addEvent(div2, 'show', function() {
        alert(2);
    });
    fireEvent(div2, 'show');
}
function addEvent(obj, events, fn) {
    // obj 楼层
    // listners  书架
    // fn   书
    obj.listeners = obj.listeners || {};
    obj.listeners[events] = obj.listeners[events] || [];
    obj.listeners[events].push(fn);
    if (obj.addEventListener) {
        obj.addEventListener(events, fn, false);
    } else {
        obj.attachEvent('on' + events, fn);
    }
}
// 自动调用函数
function fireEvent(obj, events) {
    console.log(obj.listeners);
    for (var i = 0; i < obj.listeners[events].length; i++) {
        obj.listeners[events][i]();
    }
}