The last discussion about the inherit

point about inherit:

　　1：subclass can get SuperClass`s message

　　2：subclass rewrite SuperClass`s message

　　3：many subclass Share a piece of memory

 

the inherit plan in javascript

　　1：subClass get superClass by __proto__

　　2：subClass can reWrite superClass

　　3：when subClass initialize，is must initialize superClass by call

　　

the principle about instence

　　current instence keeping find the attrbute by __proto__,such as:

　　

var a = new A();
a instence Object?

　　1：a.__proto__ != Object.prototype

　　2：a.__proto__ -> A.prototype so we judge：A.prototype.__proto__ == Object.protype

　　so a.__proto__.__proto__ == Object.protype, so a instence A is true