未定义不是主干网中的函数错误。

Question

我有一个html模板，其中包括骨干代码。我是backbone.whenever的新手，我试着运行代码，它显示了一个未定义的未定义的错误不是函数error.Please帮助。

  <!DOCTYPE html>
      <html>
      <head>
        <meta charset="utf-8">
        <title>hello-backbonejs</title>
      </head>
      <body>
        <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.6.1/jquery.min.js"></script>
        <script src="http://ajax.cdnjs.com/ajax/libs/json2/20110223/json2.js"></script>
        <script src="http://ajax.cdnjs.com/ajax/libs/underscore.js/1.1.6/underscore-min.js"></script>
        <script src="http://cdnjs.cloudflare.com/ajax/libs/backbone.js/1.1.0/backbone-min.js"></script>



        <script type="text/javascript">
        (function($){
        //ListView class: Our main app view.

      var ListView = Backbone.View.extend({
        el: $('body'), // attaches `this.el` to an existing element.

    //initialize(): Automatically called upon instantiation. Where you make all types of bindings, excluding UI events, such as clicks, etc.

        initialize: function(){
          _.bindAll(this, 'render'); // fixes loss of context for 'this' within methods

           this.render(); // not all views are self-rendering. This one is.
        },

    //render(): Function in charge of rendering the entire view in this.el. Needs to be manually called by the user.

        render: function(){
          $(this.el).append("<ul> <li>hello world</li> </ul>");
        }
      });

    //listView instance: Instantiate main app view.

      var listView = new ListView();
        })(jQuery);
        </script>
      </body>
      </html>

Answer 1

这个问题是由旧版本的underscore.js引起的。将其更改为较新版本后，错误就消失了，您的代码也可以工作了。

http://jsfiddle.net/3dH24/4/

演示中使用的下划线版本：

//cdnjs.cloudflare.com/ajax/libs/underscore.js/1.6.0/underscore-min.js

如果您查看jsFiddle上左侧手风琴菜单中的外部参考资料，您可以看到导入的文件(在头中)。