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  • js继承的几种实现方法

     

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

    <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title></title> </head> <body> <script type="text/javascript">

     // ------------------------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("</br>"); } }

    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("</br>");}}

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

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

    document.write("");document.write("</br>");

    //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+"</br>");}

    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("</br>");

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

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

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

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

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

    document.write("");document.write("</br>");

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

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

    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 + "<br>");}}

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

    document.write("");document.write("</br>");

    //--------------------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+"<br>");}

    function Student() { }

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

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

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

    document.write("");document.write("</br>");

    //--------------------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 + "<br>");}

    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 + "<br>");}

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

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

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  • 原文地址:https://www.cnblogs.com/_zjl/p/2258355.html
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