1 //自定义事件
2 function EventTarget() {
3 this.handlers =
{};
4 }
5 EventTarget.prototype =
{
6 constructor: EventTarget,
7 //注册
8 addHandler:
function(type, handler) {
9 if (
typeof this.handlers[type] == "undefined"
) {
10 this.handlers[type] =
[];
11 }
12 this.handlers[type].push(handler);
13 },
14 //触发
15 fire:
function(event) {
16 if (!
event.target) {
17 event.target =
this;
18 }
19 if (
this.handlers[event.type]
instanceof Array) {
20 var handlers =
this.handlers[event.type];
21 for (
var i = 0, len = handlers.length; i < len; i++
) {
22 handlers[i](event);
23 }
24 }
25 },
26 //注销
27 removeHandler:
function(type, handler) {
28 if (
this.handlers[type]
instanceof Array) {
29 var handlers =
this.handlers[type];
30 for (
var i = 0, len = handlers.length; i < len; i++
) {
31 if (handlers[i] ===
handler) {
32 break;
33 }
34 }
35 handlers.splice(i, 1
);
36 }
37 }
38 };
1 //使用方法
2 function handleMessage(event) {
3 alert("Message received: " +
event.message);
4 }
5 //创建一个新对象
6 var target =
new EventTarget();
7 //添加一个事件处理程序
8 target.addHandler("message"
, handleMessage);
9 //触发事件
10 target.fire({
11 type: "message"
,
12 message: "Hello world!"
13 });
14 //删除事件处理程序
15 target.removeHandler("message"
, handleMessage);
16 //再次，应没有处理程序
17 target.fire({
18 type: "message"
,
19 message: "Hello world!"
20 });
转载于:https://www.cnblogs.com/qzsonline/archive/2012/06/13/2547895.html
