观察者模式

var Observer = (function(){
    var _messages = {};
    return {
        regist : function(type,fn){
            if(typeof _messages[type] === 'undefined'){
                _messages[type] = [fn];
            }else{
                _messages[type].push(fn);
            }
        },
        fire : function(type, args){
            if(!_messages[type])
                return;
            var events = {
                    type : type,
                    args : args || {}
                },
                i=0,
                len = _messages[type].length;
            for(;i < len; i++){
                _messages[type][i].call(this, events);
            }
        },
        remove : function(type){
            if(_messages[type] instanceof Array){
                var i = _messages[type].length - 1;
                for(; i >= 0; i--){
                    _messages[type][i] === fn && _messages[type].splie(i, 1);
                }
            }
        }
    }
})();

Observer.regist('test', function(e){
    console.log(e.type, e.args.msg);
});

Observer.fire('test', {msg:'传递参数'});