John Resig的javascript简单继承模型

var Person = Class.extend({
  init: function(isDancing){//构造方法
    this.dancing = isDancing;
  },
  dance: function(){ //类似Class的方法
    return this.dancing;
  }
});
var Ninja = Person.extend({
  init: function(){//构造方法
    this._super( false );
  },
  dance: function(){ //类似Class的方法
    // Call the inherited version of dance()
    return this._super();
  },
  swingSword: function(){
    return true;
  }
});
//下面是经典的对象使用方法
var p = new Person(true);
p.dance(); // => true

var n = new Ninja();
n.dance(); // => false
n.swingSword(); // => true

// Should all be true
p instanceof Person && p instanceof Class &&
n instanceof Ninja && n instanceof Person && n instanceof Class