---
title: "Global object - Glossary | MDN"
chunk: 1/3
source: "https://developer.mozilla.org/en-US/docs/Glossary/Global_object"
category: "reference"
tags: "web, html, css, javascript, documentation"
date_saved: "2026-05-05T05:32:35.660821+00:00"
instance: "kb-cron"
---

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  1. [Glossary](https://developer.mozilla.org/en-US/docs/Glossary)
  2. [Global object](https://developer.mozilla.org/en-US/docs/Glossary/Global_object)

# Global object
The **global object** in JavaScript is an [object](https://developer.mozilla.org/en-US/docs/Glossary/Object) which represents the [global scope](https://developer.mozilla.org/en-US/docs/Glossary/Global_scope).
**Note:** _Globally available objects_ , which are objects in the [global scope](https://developer.mozilla.org/en-US/docs/Glossary/Global_scope), are sometimes also referred to as global objects, but strictly speaking, there is only one global object per environment.
In each JavaScript environment, there's always a global object defined. The global object's interface depends on the execution context in which the script is running. For example:
  * In a web browser, any code which the script doesn't specifically start up as a background task has a [`Window`](https://developer.mozilla.org/en-US/docs/Web/API/Window) as its global object. This is the vast majority of JavaScript code on the Web.
  * Code running in a [`Worker`](https://developer.mozilla.org/en-US/docs/Web/API/Worker) has a [`WorkerGlobalScope`](https://developer.mozilla.org/en-US/docs/Web/API/WorkerGlobalScope) object as its global object.
  * Scripts running under [Node.js](https://developer.mozilla.org/en-US/docs/Glossary/Node.js) have an object called [`global`](https://nodejs.org/api/globals.html#globals_global) as their global object.

The [`globalThis`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/globalThis) global property allows one to access the global object regardless of the current environment.
[`var`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/var) statements and [function declarations](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/function) at the top level of a script create properties of the global object. On the other hand, [`let`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/let) and [`const`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/const) declarations never create properties of the global object.
The properties of the global object are automatically added to the [global scope](https://developer.mozilla.org/en-US/docs/Glossary/Global_scope).
In JavaScript, the global object always holds a reference to itself:
## In this article
  * [See also](https://developer.mozilla.org/en-US/docs/Glossary/Global_object#see_also)

##  [See also](https://developer.mozilla.org/en-US/docs/Glossary/Global_object#see_also)
  * Related glossary terms: 
    * [global scope](https://developer.mozilla.org/en-US/docs/Glossary/Global_scope)
    * [object](https://developer.mozilla.org/en-US/docs/Glossary/Object)
  * [`globalThis`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/globalThis)
  * [`Window`](https://developer.mozilla.org/en-US/docs/Web/API/Window)
  * [`WorkerGlobalScope`](https://developer.mozilla.org/en-US/docs/Web/API/WorkerGlobalScope)
  * [`Window.window`](https://developer.mozilla.org/en-US/docs/Web/API/Window/window)
  * [`Window.self`](https://developer.mozilla.org/en-US/docs/Web/API/Window/self)
  * [`Window.frames`](https://developer.mozilla.org/en-US/docs/Web/API/Window/frames)
  * [`WorkerGlobalScope.self`](https://developer.mozilla.org/en-US/docs/Web/API/WorkerGlobalScope/self)
  * [`global`](https://nodejs.org/api/globals.html#globals_global)