---
id: kb-2026-00107
title: Page Visibility API
schema_type: TechArticle
category: computer-science
language: en
confidence: medium
last_verified: '2026-05-28'
created_date: '2026-05-22'
generation_method: human_only
derived_from_human_seed: true
conflict_of_interest: none_declared
is_live_document: false
data_period: static
atomic_facts:
  - id: fact-computer-science-001
    statement: >-
      MDN describes the Page Visibility API as letting pages know when a document is visible or
      hidden.
    source_title: Page Visibility API - Web APIs | MDN
    source_url: https://developer.mozilla.org/en-US/docs/Web/API/Page_Visibility_API
    confidence: medium
  - id: fact-computer-science-002
    statement: MDN documents document.visibilityState as returning the visibility state of the document.
    source_title: 'Document: visibilityState property - Web APIs | MDN'
    source_url: https://developer.mozilla.org/en-US/docs/Web/API/Document/visibilityState
    confidence: medium
  - id: fact-computer-science-003
    statement: >-
      The W3C Page Visibility Level 2 specification defines the visibilitychange event for document
      visibility changes.
    source_title: Page Visibility Level 2
    source_url: https://www.w3.org/TR/page-visibility-2/
    confidence: medium
completeness: 0.88
known_gaps:
  - >-
    Coverage intentionally narrowed to directly sourced public evidence; adjacent subtopics are not
    exhaustively covered.
disputed_statements: []
primary_sources:
  - title: Page Visibility API - Web APIs | MDN
    type: documentation
    year: 2025
    url: https://developer.mozilla.org/en-US/docs/Web/API/Page_Visibility_API
    institution: Mozilla
  - title: 'Document: visibilityState property - Web APIs | MDN'
    type: documentation
    year: 2025
    url: https://developer.mozilla.org/en-US/docs/Web/API/Document/visibilityState
    institution: Mozilla
  - title: Page Visibility Level 2
    type: standard
    year: 2023
    url: https://www.w3.org/TR/page-visibility-2/
    institution: W3C
secondary_sources: []
updated: '2026-05-28'
---
## TL;DR

The Page Visibility API lets web applications observe whether a document is visible or hidden. This repair keeps only the document visibility state and event model from MDN and W3C references.

## Core Explanation

A page can read document.visibilityState and listen for visibilitychange. That makes it possible to pause work or update state when a tab is hidden or visible without relying on unsupported assumptions about user attention.

## Further Reading

- [Page Visibility API - Web APIs | MDN](https://developer.mozilla.org/en-US/docs/Web/API/Page_Visibility_API)
- [Document: visibilityState property - Web APIs | MDN](https://developer.mozilla.org/en-US/docs/Web/API/Document/visibilityState)
- [Page Visibility Level 2](https://www.w3.org/TR/page-visibility-2/)

## Related Articles

- [API Gateway](../api-gateway.md)
- [Broadcast Channel API](../broadcast-channel-api.md)
- [Canvas API](../canvas-api.md)