The font event API is out in Chrome and coming in Firefox 36 but you can use it now with this polyfill
Jonathan Suh writes:
Also see http://caniuse.com/#feat=font-loading
Read the full article Jonathan Suh
Essentially, what you want from a polyfill delivery system is a way of sending one single copy of each of the best polyfills, in the right order (respecting dependencies), to just the browsers that lack a native implementation. The polyfill service does this by reading the User-Agent HTTP header and then using it to find the list of polyfills that are suitable for that browser and its specific version. Typically once a browser version is released, its feature set does not change until its next release.
Get started today with this one line:
Read the full article at ft.com