How to know when font-face has been applied

I found a solution after wondering why IE doesn't suffer from this problem.

Firefox and Chrome/Safari triggers the DOMContentLoaded event before font-face is applied, thus causing the problem.

The solution is to not listen for DOMContentLoaded but instead go oldschool and listen to onreadystatechange and wait until the document.readyState === 'complete' which is always triggered after font-face is applied (as far as I can tell by my tests) - which is of course what always happens in IE since it doesn't support DOMContentLoaded.

So basically you can roll-your-own event in jQuery called fontfaceapplied - maybe it should be built in ;)

document.onreadystatechange = function() {    if (document.readyState === 'complete')         $(document).trigger('fontfaceapplied');};

Funny fact: Opera does it right and waits to trigger DOMContentLoaded until font-face is applied.

ES6 update:

The question post is for many years ago which the IEs version 8 and earlier were still alive and even Ecmascript version 6 was not released, but now you can write callbacks on document.fonts events. eg:

document.fonts.onloadingdone = () => {  // do something after all fonts are loaded};

For more information see this post.

Setting the function to trigger after a timeout of 200ms solves this issue when using Google Fonts.

There's a noticeable jump, but there usually is for equal heights stuff, for the purists this might not be perfect but it works cross browser.