javascript面向对象
初学javascript,感觉javascript的面向对象编程还是很有意思的,在此记录下来.
面向对象的三大特征:封装,继承,多态
(多态还没搞明白)
1.面向对象:定义一个对象
1.1:方式一,直接{ }
var Person = {
//properties
name:"myNmae",
age:12,
eat:function(){
console.log("I'm eating!");
}
}
//访问
Person.name; //myNmae
Person.age; //12
Person.eat(); //"I'm eating"
1.2:方式二,函数构造器,类似class的概念
//无参
function Person(){
}
Person.prototype = {
name:"myNmae",
age:12,
run:function(){
console.log("I'm running!");
}
}
//实例化
var p = new Person();
//访问
p.name; //myName
p.age; //12
p.run(); //"I'm running!"
//有参数
function Person1(name){
this._name = name;
}
Person1.prototype = {
age : 13
}
2.javascript的继承
function People(){
}
People.prototype.say = function(){
console.log("Hello!");
}
//Student继承于People
function Student(){
}
Student.prototype = new People();
var stu = new Student();
stu.say(); //"Hello!"
3.重写
function People(){
}
People.prototype.say = function(){
console.log("Hello!");
}
//Student继承于People
function Student(){
}
Student.prototype = new People();
var superSay = Student.prototype.say;
Student.prototype.say = function(){
//调用父类的函数
superSay.call(this); //"Hello!"
console.log(" student say hello!");
}
var stu = new Student();
stu.say(); //"Hello!" + "student say hello!"
4.封装,通过(function(){ //properties的模式 }());达到封装
(function(){
var secret = "secret"; //外面不能直接访问这个成员
function People(){
}
People.prototype.say = function(){
console.log("Hello!");
}
//对外接口
window.People = People;
}());
;
(function(){
//Student继承于People
function Student(){
}
Student.prototype = new People();
var superSay = Student.prototype.say;
Student.prototype.say = function(){
//调用父类的函数
superSay.call(this); //"Hello!"
console.log(" student say hello!");
}
//对外的接口
window.Student = Student;
}());
var stu = new Student();
stu.say(); //"Hello!" + "student say hello!"
5.另外的一种写法,面向对象:使用空对象承载成员信息
(function(){
function Person(){
_this = {};
_this.sayHello = function(){
alert("Hello");
}
return _this;
}
window.Person = Person;
}());
//继承
(function(){
function Teacher(){
var _this = Person();
//重写
var superSay = _this.sayHello;
_this.sayHello = function(){
superSay.call(_this);
alert("Haha!");
}
return _this;
}
window.Teacher = Teacher;
}());
var t = Teacher();
t.sayHello(); //"Hello" + "Haha!"
