openseadragon/openseadragon — pull request #103 by acdha (2013-05-23 14:18:52+00:00)
Title: Paranoid requestAnimationFrame for antique Firefox

Very old versions of Firefox - e.g. Firefox 7 - have window.requestAnimationFrame but not cancelAnimationFrame. This is a very old release so the easiest fix is simply to check for both of the functions which we intend to call and fall back on traditional behaviour if both aren't present.