WebKit supports a 'beforeload' event [1] which is supported in shipping Safari and Chrome[2] and apparently has (enabled) the real-world use-cases of:
1. Performance. Reducing bandwidth use / HTTP requests, e.g. AdBlock extension[2] 2. Clientside transformations, e.g. Mobify[3] As might be expected, there is at least one use-case for a complementary 'afterload' event: 1. Downloadable fonts - people who want to use custom fonts for drawing in the canvas element need to know when a font has loaded. 'afterload' seems like a good way to know that, since it happens as a side effect of actually using it and fonts don't have an explicit load API like images do.[4] Safari and Chrome have already shipped 'beforeload', and Mozilla is strongly considering implementing 'beforeload' and 'afterload'.[4] Should 'beforeload'/'afterload' be explicitly specified and added to the web platform? Rather than attempt to provide a specific detailed design at this point, I'd prefer to ask for the list's consideration/discussion, and leave detailed specification of the two events to the editor. Thanks, Tantek [1] http://developer.apple.com/library/safari/documentation/Tools/Conceptual/SafariExtensionGuide/MessagesandProxies/MessagesandProxies.html [2] http://google-chrome-browser.com/tags/beforeload [3] http://mobify.com/static/talks/client-side-transformations.html#27 [4] https://bugzilla.mozilla.org/show_bug.cgi?id=715695#c9 -- http://tantek.com/ - I made an HTML5 tutorial! http://tantek.com/html5
