JQuery 构造学习

(function(a,undefined){

    var doc = window.document,
        loc = window.location,
        nav = window.navigator;

    var jQuery = function(selector){
        return new jQuery.fn.init(selector);
    }

    jQuery.fn = jQuery.prototype =  {
        constructor: jQuery,
        init :function(selector){
            var element = document.getElementById(selector);
            this.length = 1;
            this[0] = element;
            return this;
        },
        length : 0,
        splice: [].splice
    };
    jQuery.fn.init.prototype = jQuery.fn;
    jQuery.extend = jQuery.fn.extend = function(o) {
        return this;
    }

    window.Dirt = window.$ = window.jQuery = jQuery;

})(window);