Constructor - MDN Web Docs Glossary: Definitions of Web-related terms 编辑

A constructor belongs to a particular class object that is instantiated. The constructor initializes this object and can provide access to its private information. The concept of a constructor can be applied to most object-oriented programming languages. Essentially, a constructor in JavaScript is usually declared at the instance of a class.

Syntax

// This is a generic default constructor class Default
function Default() {
}

// This is an overloaded constructor class Overloaded
// with parameter arguments
function Overloaded(arg1, arg2, ...,argN){
}

To call the constructor of the class in JavaScript, use a new operator to assign a new object reference to a variable.

function Default() {
}

// A new reference of a Default object assigned to a
// local variable defaultReference
var defaultReference = new Default();

Learn more

General knowledge

• Constructor on Wikipedia

Technical reference

• The constructor in object oriented programming for JavaScript on MDN
• New operator in JavaScript on MDN