JavaScript 面向对象继承实现：基于原型链的属性复制

 
var JsObject = {} || new Object();
JsObject.extend = function(subClass, superClass){
// 检查子类subClass是否已定义，若未定义则重新定义类。
if(typeof subClass == "undefined")subClass = function(){};
// 若父类superClass为函数，则将其实例化为对象
if(typeof superClass == "function")superClass = new superClass();
// 遍历父类superClass对象的属性与方法
for(var p in superClass)
{ 
/* 将父类superClass对象的属性与方法复制到子类prototype对象中，
从而使子类继承父类的所有特性 */
subClass.prototype[p] = superClass[p];
} 
return subClass;
}; 
function Student()
{ 
this.name = "张三";
this.updateName = function(name){
this.name = name;
} 
} 
function Class1()
{ 
this.sex = "男";
this.updateSex = function(sex){
this.sex = sex;
} 
} 
// 定义类Class1继承Student类
Class1 = JsObject.extend(Class1, Student);
var obj = new Class1();
alert(obj.sex);
alert(obj.name);
obj.updateSex("女");
obj.updateName("玛丽");
alert(obj.sex);
alert(obj.name);

输出结果：男，张三，女，玛丽