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Zach Leatherman

A Historical Look at FOUT and FOIT

19 Sep 2017 Zach Leatherman 4 min read

Prerequisite: not sure what FOUT or FOIT are? Read the definitions on the Web Font Loading Glossary.

For a recent talk at CSS-Minsk-JS, I did some research on the history of default font loading behaviors. I thought it was interesting, so I packaged it up below.

YearBehaviorDescription
1997CSS 2 Fonts W3C Working Draft
1997FOUT (1st)Internet Explorer (v4) added @font-face support, first introducing FOUT to the world.
1998CSS 2 Fonts W3C Recommendation
2008 Nov 12FOIT (1st)Safari (v3.2) added @font-face support, first introducing FOIT to the world.
2008 Dec 11FOIT (2nd)Chrome (v1.0) added @font-face support (was using WebKit 528)
2009 Jun 29FOUT (2nd)Firefox (v3.5) added @font-face support
2009 Aug 31FOUTOpera (v10.1) added support
2010 Apr 2FOITMobile Safari (v3.2) added @font-face support (SVG format only)
2011 Mar 8FOITMobile Safari (v4.3) added a few more popular @font-face formats
2011 Mar 22FOIT 3s (1st)Firefox (v4.0) switched to add a FOIT timeout, the first browser to FOIT with a timeout.
2012 NovFOIT 3s (2nd)Opera (v12.1) switched to add a FOIT timeout
2013 JulFOITChrome (v28) switched to the Blink rendering engine, keeping the FOIT
2013 Jul 2FOITOpera (v15) switched to the Blink rendering engine, switching from FOIT with a timeout to FOIT without a timeout.
2014 MayFOIT 3sChrome (v35) switched to add a FOIT timeout
2014 JunFOIT 3sOpera (v22) followed Blink and added a FOIT timeout (again)
2015 MarFOUTEdge (v12) released, maintaining IE’s beautiful default FOUT behavior.
2016 Sep 20FOIT 3sSafari (v10) finally added a FOIT timeout, almost eight full years after introducing FOIT to the world.

Browsers implementing a FOUT/FOIT/FOIT-3s behavior first (trailblazers) are denoted as (1st) above. Browsers second to implement an existing behavior (two makes a crowd) are denoted as (2nd) above.

This list is limited to stable releases, and does not include information about dev channel/beta/technology previews.

Highlights

  • Microsoft’s adherence to FOUT. It’s the most reliable way to render web fonts without the perceived performance penalties and race conditions that come with FOIT so honestly, I admire this. They were first and they’ve stuck to their guns.
  • Opera has been the most volatile of the bunch, mostly because of the unfortunately timing of their rendering engine switch.
  • I was disappointed at how much influence WebKit/Safari’s choices had on other browsers. I know how much of a pain point the default FOIT behavior is for developers and so it’s been a little disheartening to read those early bug tracker discussions. I’m glad they’ve added a FOIT timeout but we need a cross-browser way to easily control FOIT and FOUT—we need wider support for the font-display descriptor.