Javascript 面向对象编程(一):封装
http://www.ruanyifeng.com/blog/2010/05/object-oriented_javascript_encapsulation.html
Javascript面向对象编程(二):构造函数的继承
http://www.ruanyifeng.com/blog/2010/05/object-oriented_javascript_inheritance.html
Javascript面向对象编程(三):非构造函数的继承
http://www.ruanyifeng.com/blog/2010/05/object-oriented_javascript_inheritance_continued.html