!!function(){var obj = {nama1: 123,name2: 1234,name3: 12345,addname:function(name,fn){if( !this[name] ){ ?//判斷是否存在這個(gè)對(duì)象this[name] = fn; ?//不存在就添加進(jìn)去。}else{console.log( name + "已經(jīng)存在");}return this;? //不懂這里的return this 是干嘛用的？？？？}};//向obj里面添加對(duì)象。obj.addname('name4',function(){return "123456";}).addname('name2',function(){return "1234";});}();