---
title: "Browsing context - Glossary | MDN"
chunk: 1/3
source: "https://developer.mozilla.org/en-US/docs/Glossary/Browsing_context"
category: "reference"
tags: "web, html, css, javascript, documentation"
date_saved: "2026-05-05T05:25:48.374289+00:00"
instance: "kb-cron"
---

  * [Skip to main content](https://developer.mozilla.org/en-US/docs/Glossary/Browsing_context#content)
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  * [Using the Web animation API](https://developer.mozilla.org/en-US/docs/Web/API/Web_Animations_API/Using_the_Web_Animations_API)
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Learn HTML
    
  * [Structuring content with HTML module](https://developer.mozilla.org/en-US/docs/Learn_web_development/Core/Structuring_content)

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[Blog](https://developer.mozilla.org/en-US/blog/)
  1. [Glossary](https://developer.mozilla.org/en-US/docs/Glossary)
  2. [Browsing context](https://developer.mozilla.org/en-US/docs/Glossary/Browsing_context)

# Browsing context
A **browsing context** is an environment in which a browser displays a [`Document`](https://developer.mozilla.org/en-US/docs/Web/API/Document). In modern browsers, it usually is a _tab_ , but it can be a _window_ , a _popup_ , a [web application](https://developer.mozilla.org/en-US/docs/Web/Progressive_web_apps), or even a part of a page such as a _frame_ or an _iframe_.
Each browsing context has an origin (that of the active document) and an ordered history of previously displayed documents. Communication and resource sharing between browsing contexts is constrained, in particular between cross-origin contexts. For example, a [`BroadcastChannel`](https://developer.mozilla.org/en-US/docs/Web/API/BroadcastChannel) can only be opened and used to communicate between same-origin contexts.
A browsing context may be part of a **browsing context group** , which is a set of **browsing contexts** that share common contexts, such as history, cookies, storage mechanisms and so on. The browsing contexts within a group retain references to each other, and therefore, can inspect each other's global objects and post messages to each other.
By default, a document opened in a browser context group is opened in the same group, whether or not it is cross-origin or same-origin. The [`Cross-Origin-Opener-Policy`](https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Headers/Cross-Origin-Opener-Policy) can be used to control whether the document is instead opened in its own new browsing context group and [cross-origin isolated](https://developer.mozilla.org/en-US/docs/Web/API/Window/crossOriginIsolated "cross-origin isolated") from other contexts (in particular cross-origin contexts). This can mitigate the risk of cross-origin attacks and the side-channel attacks referred to as [XS-Leaks](https://xsleaks.dev/).
## In this article
  * [See also](https://developer.mozilla.org/en-US/docs/Glossary/Browsing_context#see_also)

##  [See also](https://developer.mozilla.org/en-US/docs/Glossary/Browsing_context#see_also)
  * Related glossary terms: 
    * [Origin](https://developer.mozilla.org/en-US/docs/Glossary/Origin)