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Fullscreen Tester

Test fullscreen mode for free. Try the Fullscreen API on a live demo box, see your screen capabilities, and get a log of fullscreen events.

Fullscreen demo

Press the button to take the demo box fullscreen.

Demo box
This box goes fullscreen

Fullscreen not active.

Screen info

Event log

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What the tester checks

The demo box exercises the real Fullscreen API: entering fullscreen, exiting, and the Esc key path. The event log records every transition with a timestamp, useful when debugging kiosk or presentation setups.

The screen info panel reports fullscreen support, screen and viewport size, pixel ratio and orientation in one glance.

When fullscreen gets blocked

Browsers only allow fullscreen from a user gesture like a click, so programmatic requests on page load are rejected. Some embedded iframes also block it unless they carry the allowfullscreen attribute.

If the button fails, the status line shows the exact rejection reason, which usually points straight at the fix.

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Fullscreen Tester FAQs

Why does fullscreen need a click?
Browsers require a user gesture to prevent sites from hijacking the screen uninvited. A button press is the standard trigger.
How do I exit fullscreen?
Press Esc, or use the Exit button here. The API also exposes document.exitFullscreen() for your own code.
Does it work on mobile browsers?
Mostly yes on Android Chrome. iPhone Safari supports fullscreen for video elements but historically limits generic element fullscreen.
What is devicePixelRatio?
How many physical pixels make up one CSS pixel. A ratio of 2 means a 1920-wide screen reports 960 CSS pixels wide.
Can I test a specific element?
This page tests its demo box. The same requestFullscreen() call works on any element in your own pages.
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