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FontFaceSet.check

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.

Syntax

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

Returns

A Boolean that is true if the font list is available

Parameters

font: a font specification using the CSS value syntax, e.g. "italic bold 16px Roboto"
text: limit the font faces to those whose Unicode range contains at least one of the characters in text. This does not check for individual glyph coverage.

Examples

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.

Specifications

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

Browser compatibilityUpdate compatibility data on GitHub

	Desktop
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari
Basic support	35	?	41	?	?	?

	Mobile
	Android webview	Chrome for Android	Edge Mobile	Firefox for Android	Opera for Android	iOS Safari	Samsung Internet
Basic support	37	35	?	41	?	?	?

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https://developer.mozilla.org/en-US/docs/Web/API/FontFaceSet/check