Better font events with the native font loading API
Typekit kits are now using the CSS font loading API, which is available in recent versions of Chrome, Firefox, and Opera. The font loading API provides native functionality for loading and manipulating web fonts. It also provides font events that will tell you when a font loads or fails to load.
Before the introduction of the native API, we detected font loading by inserting test elements in the page. These elements were regularly polled for width to see if the font had loaded. This process is very expensive because it triggers a page wide style reflow each time the elements are checked. Using the native API, we can bypass this process completely, which results in a big performance improvement.
Browsers that do not support the native API fall back to the old behavior. We hope other browser vendors will join Google, Mozilla, and Opera and implement this new API for faster and more reliable font events.
If you wish to use the new functionality, please republish your kit(s). You can do this in the kit editor, or on the kit management page. Please let us know at firstname.lastname@example.org if you have any questions concerning this change.