The All-In-One Almost-Alphabetical Guide to Detecting Everything (Confused? Read Detecting HTML5 Features for a conceptual introduction. Want an all-in-one library instead? Try Modernizr.) <audio> return !!document.createElement('audio').canPlayType; <audio> in MP3 format var a = document.createElement('audio'); return !!(a.canPlayType && a.canPlayType('audio/mpeg;').replace(/no/, '')); <audio> in