面向对象的javascript语言

1.封装
function Car(sColor,iDoors,iMpg){
      this.color = sColor;
      this.doors = iDoors;
      this.mpg   = iMpg;
      this.drivers = new Array("Mike","Sue");

       if(typeof Car._initialized == "undefined"){
        
          Car.prototype.showColor = function(){
                alert(this.color);
          }
          Car._initialized = true;
       }
}
2.继承
a.对象冒充
  function ClassA(sColor){
      this.color = sColor;
      this.sayColor = function(){
           alert(this.color);
      };
  }

  function ClassB(sColor){
       this.newMethod = ClassA;
       this.newMethod(sColor);
       delete this.newMethod;

       this.name = sName;
       this.sayName = function(){
            alert(this.name);
       };
  }

  var objA = new ClassA("red");
  var objB = new ClassB("blue","Nicholas");
  objA.sayColor(); // "red"
  objB.sayColor(); // "blue"
  objB.sayName();  // "Nicholas"

//注意：对象冒充可以实现多重继承
b.call()方法
function ClassB(sColor, sName){
     //this.newMethod = ClassA;
     //this.newMethod(sColor);
     //delete this.newMethod;
     ClassA.call(this,sColor);

     this.name = sName;
     this.sayName = function(){
          alert(this.name);
     };
}
c.apply()方法
function ClassB(sColor ,sName){
    //this.newMethod = ClassA;
    //this.newMethod(sColor);
    //delete this.newMethod;

    ClassA.apply(this, new Array(sColor));
 
    this.name = sName;
    this.sayName = function(){
         alert(this.name);
    };
}
d.混合方法
function ClassA(sColor){
     this.color = sColor;
}
ClassA.prototype.sayColor = function(){
    alert(this.color);
};
function ClassB(sColor ,sName){
     ClassA.call(this,sColor);
}
ClassB.prototype = new ClassA();
ClassB.prototype.sayName = function(){
    alert(this.name);
};