var Obsever = {};
　//添加观察者;    var add = function (name, callback){        if(typeof name == ‘string‘ && typeof callback == ‘function‘){            Obsever[name] ? Obsever[name].push(callback) : Obsever[name] = [callback];        }    }
　//删除观察者;    var remove = function (name, callback){
　　　　if(typeof name == ‘string‘){        var list = Obsever[name];
     　　if(list){        　　if( callback == null){           　　delete Obsever[name];        　　}else{            　　for (var i = 0; i < list.length; i++){                　　if(callback == list[i]){                    　　list[i] = null;               　　 }           　　 }        　　}    　　}
　　}
}
　　//调用观测者;    var broadcase = function (name){        var list = Obsever[name];        if(list){for(var i = 0 ; i < list.length; i++){                var cb = list[i];                if(typeof cb == ‘function‘){                    cb.apply(cb,Array.prototype.slice.call(arguments,1));                }else{                    list.splice(i,1);                    i--;                }            }        }    }add(‘teacher‘,function(message){alert(message)});broadcase(‘teacher‘,‘Hi,goodNight‘);