jquery.prototype.data

jquery运行的闭包中生成变量expando = 'jQuery'  +  new Date

 

然后在闭包中弄了1个数

 

每次调data的时候+1

 

往元素的expando 属性上挂 这个数

 

然后将属性存到$.cache中

 

键为元素的expando对应的数字

 

值为存储的东西

 

 

(function($) {

       var expando = 'jQuery' + new Date;

       var num = 0;

       $.fn.data = function(a,b) {

             return this.each(function() {

                     if(!b) {

                           if(!this.expando) {

                           this.expando = ++num;

                           $.cache[num] = {};

 

                     }

                     $.cache[num][a] = b;

                     } else {

                             if(!this.expando) return null;

                             return $.cache[this.expando][a];

                    }

 

             });

        }

})(jQuery);