Fullscreen Test
Test your browser's fullscreen capability. Verify that fullscreen mode works correctly on your device and browser.
Fullscreen Test
Test whether your browser supports the Fullscreen API.
How Does the Fullscreen Test Work?
- Click the button to request fullscreen mode through the browser's Fullscreen API.
- Your browser window will expand to fill the entire screen.
- Press Escape or click the exit button to return to normal mode.
- The tool also checks whether your browser supports the Fullscreen API.
How the Fullscreen API Works
The Fullscreen API is a web standard that lets any HTML element expand to occupy the entire screen, hiding the browser chrome, taskbar, and all other UI. Unlike pressing F11, which is a browser-level action the page can't control, the Fullscreen API is triggered by JavaScript and gives the website fine-grained control over what element goes fullscreen and how it's styled. Video players use it to go fullscreen without leaving the page, games use it to claim the whole display, and presentation tools use it for distraction-free slide decks.
Browsers enforce a critical security rule: fullscreen can only be requested in response to a user gesture — a click, tap, or key press. This prevents malicious sites from hijacking your screen without your consent. If you call requestFullscreen() outside a user gesture handler, the browser silently ignores it.
Common Fullscreen Issues and Fixes
The most frequent problem is fullscreen not activating at all. This usually happens when the request isn't tied to a direct user interaction, or when the page is loaded inside an iframe that lacks the allow="fullscreen" attribute. Embedded widgets, preview panels, and sandboxed frames often block fullscreen for security reasons.
Another common issue is fullscreen exiting unexpectedly. Any JavaScript alert, confirm dialog, or permission prompt will immediately pull the browser out of fullscreen. System notifications on macOS and Windows can also interrupt it. If fullscreen keeps dropping out, check whether background processes or browser extensions are triggering popups.
On multi-monitor setups, fullscreen targets whichever display currently hosts the browser window. If you want fullscreen on your secondary monitor, drag the browser window to that screen first, then trigger fullscreen. There's no API-level control over which monitor is used — the browser follows the window's position.
Browser Differences in Fullscreen Behavior
While the Fullscreen API is well-standardized, browsers implement it with subtle differences. Safari still uses the webkitRequestFullscreen prefix on older versions and applies its own styling rules to fullscreen elements. Firefox shows a brief notification bar when a page enters fullscreen, which auto-hides after a few seconds. Chrome displays a transient "press Esc to exit" message. All browsers allow exiting fullscreen with the Escape key, and all fire fullscreenchange events that your code can listen for to update UI accordingly.
Frequently Asked Questions
- Why doesn't fullscreen work?
- Some browsers require a direct user interaction (like a click) to enter fullscreen. Embedded iframes may also block fullscreen. Try using this tool directly rather than through a frame.
- Is fullscreen the same as F11?
- Not exactly. F11 is a browser-level fullscreen that hides the browser UI. The Fullscreen API is a web standard that allows websites to request fullscreen. Both achieve a similar result but work differently.