HTML5 video
In 2010, in the wake of Apple iPad launch and after Steve Jobs announced that Apple mobile devices would not support Flash, a number of high-profile sites began to serve H.264 HTML5 video instead of Adobe Flash for user-agents identifying as iPad. HTML5 video was not as widespread as Flash videos, though there were rollouts of experimental HTML5-based video players from DailyMotion (using Ogg Theora and Vorbis format), YouTube (using the H.264 and WebM formats), and Vimeo (using the H.264 format).
Comparison of HTML5 and Flash
Speaking at 'Adobe Max' in 2011, Itai Asseo likewise said that, unlike HTML5, Flash offers a way to develop applications that work across platforms. HTML5, he said, is currently implemented differently (if at all) by different browsers. Although the Flash browser plugin is not supported on the Apple iPhone OS, Flash applications can be exported to Adobe AIR, which runs on that operating system as a native application. In the same talk, Mr. Asseo lamented the return to another browser war (as seen in the late 1990s). If Flash falls out of favor, he said, web developers will either have to develop many different versions of their web sites and native applications to take into account different HTML5 implementations, deny access to browsers that do not support their version of HTML, or dramatically reduce the functionality of their sites in order to deliver content to the least-advanced browser.