js继承的几种实现方法

it2024-12-20 8

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

// ------------------------继承的第一种方式：对象冒充-----------------------------

function Parent(name) { this.name = name; this.showInfo = function () { document.write(name); document.write(""); } }

function Children(name, pwd) {//下面三行代码实现了子对象和父对象指向同一个引用//关键的代码this.method = Parent;this.method(name);delete this.method;

this.pwd = pwd;this.showMsg = function () {document.write(this.pwd);document.write("");}}

var parent = new Parent("John");var child = new Children("Bob", 123);

parent.showInfo();child.showInfo();child.showMsg();

document.write("");document.write("");

//call方法，是function里的一个方法。

//------------------------call方法简单示例-------------------------------

function test(str) {document.write(this.name + "," + str+"");}

var person = new Object();person.name = "anllin";

//相当于调用了test方法test.call(person, "welcome"); //将person赋给了test里的this。

document.write("");document.write("");

//--------------------继承的第二种方式，call方法------------------------------

function Father(name) {this.name = name;this.showName = function () {document.write(this.name + "");}}

function Sub(name, pwd) {//关键的代码Father.call(this, name);

this.pwd = pwd;this.showPwd = function () {document.write(this.pwd + " ");}}

var father = new Father("Father");var sub = new Sub("Sub", 123456);father.showName();sub.showName();sub.showPwd();

document.write("");document.write("");

//--------------------继承的第三种方式，apply方法------------------------------

function Mother(name) {this.name = name;this.showName = function () {document.write(this.name + "");}}

function Daugther(name, pwd) {//关键的代码Mother.apply(this, new Array(name));

this.pwd = pwd;this.showPwd = function () {document.write(this.pwd + " ");}}

var mother = new Father("Mother");var daugther = new Sub("Daugther", 654321);mother.showName();daugther.showName();daugther.showPwd();

document.write("");document.write("");

//--------------------继承的第四种方式，prototype chain方式------------------------------

//缺点：无法给构造函数传参数。

function Human(){ }

Human.prototype.name = "human";Human.prototype.showName = function () {document.write(this.name+" ");}

function Student() { }

//关键的代码Student.prototype = new Human();

Student.prototype.password = 456789;Student.prototype.showPwd = function () {document.write(this.password + " ");}

var human = new Human();var student = new Student();student.name = "student";human.showName();student.showName();student.showPwd();

document.write("");document.write("");

//--------------------继承的第五种方式，混合方式------------------------------

function FatherClass(name) {this.name = name;}

FatherClass.prototype.showName = function () {document.write(this.name + " ");}

function SubClass(name, pwd) {

//关键的代码

FatherClass.call(this,name);this.pwd = pwd;}

//关键的代码

SubClass.prototype = new FatherClass;

SubClass.prototype.showPwd = function () {document.write(this.pwd + " ");}

var f = new FatherClass("FatherClass");var s = new SubClass("SubClass", 45678);f.showName();s.showName();s.showPwd();

</script> </body> </html>

转载于:https://www.cnblogs.com/_zjl/archive/2011/11/22/2258355.html

最新回复(0)