JavaScript——対象継承を実現する5つの方法
3915 ワード
1.相手を偽る
function Parent(name)
{
this.name = name;
this.sayHello = function()
{
alert(this.name)
}
}
function Child(name, age)
{
//3
// this this,
// Parent this.name、sayHello, 、
this.method = Parent;
//
this.method(name);
//
delete this.method;
// this
this.age = age;
this.sayWorld = function()
{
alert(age);
}
}
var parent = new Parent(" ");
var child = new Child(" ", 20);
parent.sayHello();
child.sayHello();
child.sayWorld();
2.コールの方法//call Function , 。
// call ,call this,
// 2 ,
//call
function test(str, str2)
{
alert(this.name + ", " + str + ", " + str2);
}
var object = new Object();
object.name = "zhangsan";
//test.call test
// object this
test.call(object, "JavaScript", "hello");
//call
function Parent(name)
{
this.name = name;
this.sayHello = function()
{
alert(name);
}
}
function Child(name, age)
{
// this
Parent.call(this, name);
this.age = age;
this.sayWorld = function()
{
alert(age);
}
}
var parent = new Parent(" ");
var child = new Child(" ", 20);
parent.sayHello();
child.sayHello();
child.sayWorld();
3.アプリ方法//call apply context ( ) ,
// this ,
//call apply , ,apply
function Parent(name)
{
this.name = name;
this.sayHello = function()
{
alert(name);
}
}
function Child(name, age)
{
Parent.apply(this, new Array(name));
this.age = age;
this.sayWorld = function()
{
alert(age);
}
}
var parent = new Parent(" ");
var child = new Child(" ", 30);
parent.sayHello();
child.sayHello();
child.sayWorld();
4.プロトタイプチェーン方式(prototype chain)//
function Parent()
{
}
Parent.prototype.name = " ";
Parent.prototype.sayHello = function()
{
alert(this.name);
}
function Child()
{
}
//
Child.prototype = new Parent();
Child.prototype.age = 20;
Child.prototype.sayWorld = function()
{
alert(this.age);
}
var child = new Child();
child.sayHello();
child.sayWorld();
5.混合方式(プロトタイプの璎の弊害を克服した)// ,
function Parent(name)
{
this.name = name;
}
Parent.prototype.sayHello = function()
{
alert(this.name);
}
function Child(name, age)
{// this parent
Parent.call(this, name);
this.age = age;
}
//
Child.prototype = new Parent();
Child.prototype.sayWorld = function()
{
alert(this.age);
}
var child = new Child(" ", 30);
child.sayHello();
child.sayWorld();