扩展jquery问题

Question

我正在阅读此源代码，似乎有错误。任何人都可以说发生了什么

var JX = {
    extend: function(bc, sc, o) {
        var f = function() {};
        f.prototype = sc.prototype;
        bc.prototype = new f();
        bc.prototype.constructor = bc;
        bc.superclass = sc.prototype;
        for (var m in o)
            bc.prototype[m] = o[m];
    }
};
JX.Component = function() {
  JX.Component.superclass.init.apply(this, arguments);
};
JX.extend(JX.Component, jQuery, {});

$(document).ready(function() {
    var mydiv = new JX.Component(document.createElement('div'));
    mydiv.text("Hello World").click(function(){alert("You Clicked Me!")});
    mydiv.appendTo(document.body);
    alert("heee");
});

在appendTo之后出现错误