javascript面向对象中继承实现？
面向对象的基本特征有：封闭、继承、多态。
在javascript中实现继承的方法：
1. 原型链（prototype chaining）
2. call()/apply()
3. 混合方式(prototype和call()/apply()结合)
4. 对象冒充
继承的方法如下：
1、prototype原型链方式：
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functionteacher(name){ this.name=name; } teacher.prototype.sayname=function(){ console.log("nameis"+this.name); } varteacher1=newteacher("xiaoming"); teacher1.sayname(); functionstudent(name){ this.name=name; } student.prototype=newteacher() varstudent1=newstudent("xiaolan"); student1.sayname(); //nameisxiaoming //nameisxiaolan2、call()/apply()方法
function teacher(name,age){
this.name = name;
this.age = age;
this.sayhi = function(){
alert('name:'+name+", age:"+age);
}
}
function student(){
var args = arguments;
teacher.call(this,args[0],args[1]);
// teacher.apply(this,arguments);
}
var teacher1 = new teacher('xiaoming',23);
teacher1.sayhi();
var student1 = new student('xiaolan',12);
student1.sayhi();
// alert: name:xiaoming, age:23
// alert: name:xiaolan, age:12
3、混合方法【prototype,call/apply】
function teacher(name,age){
this.name = name;
this.age = age;
}
teacher.prototype.sayname = function(){
console.log('name:'+this.name);
}
teacher.prototype.sayage = function(){
console.log('age:'+this.age);
}
function student(){
var args = arguments;
teacher.call(this,args[0],args[1]);
}
student.prototype = new teacher();
var student1 = new student('xiaolin',23);
student1.sayname();
student1.sayage();
// name:xiaolin
// age:23
4、对象冒充
function person(name,age){
this.name = name;
this.age = age;
this.show = function(){
console.log(this.name+", "+this.age);
}
}
function student(name,age){
this.student = person; //将person类的构造函数赋值给this.student
this.student(name,age); //js中实际上是通过对象冒充来实现继承的
delete this.student; //移除对person的引用
}
var s = new student("小明",17);
s.show();
var p = new person("小花",18);
p.show();
// 小明, 17
// 小花, 18