发布/订阅，是一种由两个部分构成:发布者和订阅者的消息传递模式。发布者将消息发布到特定频道，而订阅者接听频道，当频道上有消息发布时将接收到通知。

1、用javascript实现Pub/Sub模式代码：

1 var PubSub = { 2            //订阅 3            subscribe : function(ev,callback){ 4                 this._callback || (this._callback = {}); 5                 (this._callback[ev] || (this._callback[ev] = [])).push(callback); 6                 return this; 7             }, 8             //取消订阅 9             unsubscribe : function(ev){10                 if(!this._callback || !this._callback[ev]){11                     return this;12                 }13                 this._callback[ev] = null;14                 delete this._callback[ev];15                 return this;16             },17              //发布18             publish : function(){19                 var callback, list, i, length, args = [].slice.call(arguments,0), ev = args.shift();20                 if(!(callback = this._callback) || !(list = this._callback[ev])){21                     return this;22                 }23                 for(i = 0, length = list.length; i < length; i++){24                       list[i].apply(this, args);25                 }26                 return this;27             }28     };29     PubSub.subscribe('wen',function(){alert('Wen!!!');}).publish('wen').unsubscribe('wen').publish('wen');