This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

The check() method of the FontFaceSet returns whether all fonts in the given font list have been loaded and are available.


bool = aFontFaceSet.check(font);
bool = aFontFaceSet.check(font, text);


A Boolean that is true if the font list is available



document.fonts.check("12px courier"); // returns true if the font courier is available at 12px

document.fonts.check("12px MyFont", "ß"); // returns true if the font 'MyFont' has a ß character. 


Specification Status Comment
CSS Font Loading Module Level 3
The definition of 'check' in that specification.
Working Draft Initial definition

Browser compatibility

Update compatibility data on GitHub
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidEdge MobileFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
Basic support
Chrome Full support 35Edge ? Firefox Full support 41IE ? Opera ? Safari ? WebView Android Full support 37Chrome Android Full support 35Edge Mobile ? Firefox Android Full support 41Opera Android ? Safari iOS ? Samsung Internet Android ?


Full support  
Full support
Compatibility unknown  
Compatibility unknown
Experimental. Expect behavior to change in the future.
Experimental. Expect behavior to change in the future.

Document Tags and Contributors

Last updated by: sideshowbarker,