JavaScript returns a reference to the array function that created this object. Property constructor-JS Tutorial-php.cn

Definition and Usage

The constructor property returns a reference to the array function that created this object.

Syntax

object.constructor

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Examples

Example 1

In this example, we will show how to use the constructor attribute:

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Output :

This is an Array

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Example 2

In this example, we will show how to use the constructor attribute:

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Output:

function employee(name, job, born) {this.name = name; this.job = job; this.born = born;}

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Example & Description

[native code] in the following code indicates that this is the underlying internal code implementation of JavaScript, and code details cannot be displayed.

// 字符串：String() var str = "张三"; alert(str.constructor); // function String() { [native code] } alert(str.constructor === String); // true // 数组：Array() var arr = [1, 2, 3]; alert(arr.constructor); // function Array() { [native code] } alert(arr.constructor === Array); // true // 数字：Number() var num = 5; alert(num.constructor); // function Number() { [native code] } alert(num.constructor === Number); // true // 自定义对象：Person() function Person(){ this.name = "CodePlayer"; } var p = new Person(); alert(p.constructor); // function Person(){ this.name = "CodePlayer"; } alert(p.constructor === Person); // true // JSON对象：Object() var o = { "name" : "张三"}; alert(o.constructor); // function Object() { [native code] } alert(o.constructor === Object); // true // 自定义函数：Function() function foo(){ alert("CodePlayer"); } alert(foo.constructor); // function Function() { [native code] } alert(foo.constructor === Function); // true // 函数的原型：bar() function bar(){ alert("CodePlayer"); } alert(bar.prototype.constructor); // function bar(){ alert("CodePlayer"); } alert(bar.prototype.constructor === bar); // true

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In order to expose the prototype object of the instance constructor, for example, if you write a plug-in, others will get the object you instantiated. If others want to extend the object, they can use instance. constructor.prototype to modify or extend the prototype object

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