笔记

目前使用最广泛的是混合的构造函数/原型方式。此外，动态原始方法也很流行，在功能上与构造函数/原型方式等价。
混合的构造函数/原型方式

function Car(sColor,iDoors,iMpg) {  
   this.color = sColor;  
   this.doors = iDoors;  
   this.mpg = iMpg;  
   this.drivers = new Array("Mike","John");  
 }  
   
 Car.prototype.showColor = function() {  
   alert(this.color);  
 };  
   
 var oCar1 = new Car("red",4,23);  
 var oCar2 = new Car("blue",3,25);  
   
 oCar1.drivers.push("Bill");  
   
 alert(oCar1.drivers);   //输出 "Mike,John,Bill"  
 alert(oCar2.drivers);   //输出 "Mike,John"

动态原型方法

    function Car(sColor,iDoors,iMpg) {  
      this.color = sColor;  
      this.doors = iDoors;  
      this.mpg = iMpg;  
      this.drivers = new Array("Mike","John");  
        
      if (typeof Car._initialized == "undefined") {  
        Car.prototype.showColor = function() {  
          alert(this.color);  
       };  
         
       Car._initialized = true;  
     }  
   }