The information below comes from: W3Schools.com.
Currently, there are 3 supported “audio formats” for the HTML5 “audio” tag: .mp3, .ogg, and .wav.
Internet Explorer supports: .mp3 (Yes), .ogg (No), .wav (No)
Chrome supports: .mp3 (Yes), .ogg (Yes), .wav (Yes)
Firefox supports: .mp3 (some browsers Yes, some No), .ogg (Yes), .wav (Yes)
Safari supports: .mp3 (Yes), .ogg (No), .wav (Yes)
Opera supports: .mp3 (No), .ogg (Yes), .wav (Yes)
Definitions: .mp3 = MP3 files, the “sound” part of the MPEG audio/video file-format.
.ogg = Ogg files, with Theora video codec and Vorbis audio codec.
.wav = WAVE files (more commonly known as WAV files), and short for “Waveform Audio File Format.”
Note: “.mp3” and “.ogg” file-formats are used as the audio file-format options for the example audio below. “.wav” files are “uncompressed” and large, and are impractical for use on web pages. (Here is an interesting article with many suggestions on how to code the HTML5 “audio” tag.)