Backbone 未定义

Question

好吧，我正在练习 backbone.js 概念，而我却卡在了这里，我的控制台显示：

main.js:1 Uncaught ReferenceError: Backbone is not defined

index.html

<html>
<head>
<meta charset="UTF-8">
<title>Backbone.js Tutorial</title>
<script src ="main.js"></script>
</head>
<body>
   <script src="js/libs/jquery-1.10.2.min.js"></script>
   <script src="js/libs/underscore-min.js"></script>
   <script src="js/libs/backbone-min.js"></script>
</body>
</html>

main.js

var Animal = Backbone.Model.extend({
    defaults: {
      name: 'Fido',
      color: 'black',
      sound: 'woof'
    },
    validate: function(attrs, options){
      if (!attrs.name){
        alert('Your animal must have a name!');
      }
      if (attrs.name.length < 2){
        alert('Your animal\'s name must have more than one letter!');
      }
    },
    sleep: function(){
      alert(this.get('name') + ' is sleeping.');
    }
});

我无法在我的控制台中创建新对象

Answer 1

为什么要将 script 标签添加到 body？

<html>
<head>
<meta charset="UTF-8">
<title>Backbone.js Tutorial</title>
   <script src="js/libs/jquery-1.10.2.min.js"></script>
   <script src="js/libs/underscore-min.js"></script>
   <script src="js/libs/backbone-min.js"></script>
   <script src="main.js"></script>
</head>
<body>
</body>
</html>

工作示例：https://jsfiddle.net/tomi77/bpz0rcg2/

Backbone 未定义

Backbone Undefined

model

backbone.js