オブジェクト向けJavaScriptの継承(一)クラス式継承

//    
function SuperClass(){
    //   
    this.superValue = true;
    //    
    this.book = ['c','java','htnl']
}

//       
SuperClass.prototype.getSuperValue =function(){
    return this.superValue;
}

//    
function SubClass(){
    this.subValue = false;
}
//    
SubClass.prototype = new SuperClass();

//       
SubClass.prototype.getSubValue = function(){
    return this.subValue;
}

//  
var a = new SubClass(); 
var b = new SubClass(); 
console.log(a.getSubValue()); //false
console.log(a.getSuperValue());  //true

console.log(a.book);//["c", "java", "htnl"]
console.log(b.book);//["c", "java", "htnl"]
a.book.push('css');
console.log(a.book);//["c", "java", "htnl", "css"]
console.log(b.book);//["c", "java", "htnl", "css"]

console.log(a.getSuperValue())//true
console.log(b.getSuperValue())//true
a.superValue = 'a';

console.log(a.getSuperValue())//a
console.log(b.getSuperValue())//true

console.log(a.getSubValue())//false
console.log(b.getSubValue())//false
a.subValue = 'sub';

console.log(a.getSubValue())//sub
console.log(b.getSubValue())//false

             ,   a b            .        (   ,    )。       ：   book   ，  subValue      ，       ，  2

  ：              ，     ，     this    ，this.superValue       ，    a，  a       a    `prototype`,    ,      `"undefined"`,          a.book.push('css');    b.book       ,            book  , a.superValue = 'a';      a      superValue   ,       `prototype` superValue  ,          .