醍醐灌顶啊有木有,大神就是大神,知识好系统!
继承
一、原型继承
1 //原型链核心是__proto__ 2 function Dog(){ 3 this.bark = function(){ 4 alert("wangwang") 5 } 6 } 7 function Hashiqi(){ 8 } 9 Hashiqi.prototype = new Dog(); 10 Hashiqi.prototype.constructor=Hashiqi;//强制更正构造器的指向
11 var dog1 = new Hashiqi(); 12 dog1.bark();//wangwang 13 Hashiqi.prototype.bark = function(){ alert("wuwu"); } 14 var dog2 = new Hashiqi(); 15 dog2.bark();//wuwu 16 var dog3 = new Dog(); 17 dog3.bark();//wangwang
二、对象冒充(使父构造函数在子构造函数中运行一遍)
临时变量
function Parent(){
}
function Child(){
this.temp = Parent;
this.temp();
delete this.temp;
}
call()和apply()
function Parent(){
}
function Child(){
Parent.call(this,var1,var2...)
//Parent.apply(this,[var1,var2...])
}
三、复制继承(把父构造函数的每个属性都复制一遍)
Object.prototype.extend = function(obj){
for(var key in obj){
if(this[key]==undefined){
this[key]=obj[key];
}
}
}
var cat = {color:"yellow",climb:function(){alert("我会爬树");}}
var tiger = {color:"yellow and black"}
tiger.extend(cat);
tiger.climb();//我会爬树
alert(tiger.color);//yellow and black
静态方法(在对象上直接添加的方法,只属于该对象)
//这是一个构造函数,也是一个对象
function Bird(){
this.wings=2;
this.fly= function(){
alert("我会飞");
}
}
//这是Bird对象的静态方法,只属于此对象
Bird.eat = function(){
alert("吃虫子")
}
var niao = new Bird();//Bird的实例,不能访问eat()