The HTML <audio> element is used to embed sound content in documents. It may contain one or more audio sources, represented using the src attribute or the <source> element: the browser will choose the most suitable one. It can also be the destination for streamed media, using a MediaStream.

In a similar manner to the <img> element, we include a path to the media we want to embed inside the src attribute; we can include other attributes to specify information such as whether we want it to autoplay and loop, whether we want to show the browser's default audio controls, etc.

The content inside the opening and closing <audio></audio> tags is shown as a fallback in browsers that don't support the element.

Browsers don't all support the same audio formats; you can provide multiple sources inside nested <source> elements, and the browser will then use the first one it understands:

<audio controls>
  <source src="myAudio.mp3" type="audio/mp3">
  <source src="myAudio.ogg" type="audio/ogg">
  <p>Your browser doesn't support HTML5 audio. Here is
     a <a href="myAudio.mp4">link to the audio</a> instead.</p>
</audio>

Other usage notes:

• If you don't specify the controls attribute, the audio player won't include the browser's default controls; you can create your own custom controls using JavaScript and the HTMLMediaElement API.
• To allow precise control over your audio content, HTMLMediaElements fire many different events.
• You can also use the Web Audio API to directly generate and manipulate audio streams from JavaScript code.
• <audio> elements can't have subtitles/captions associated with them in the same way that <video> elements can. See WebVTT and Audio by Ian Devlin for some useful information and workarounds.

A good general source of information on using HTML <audio> is the Video and audio content beginner's tutorial.

Styling with CSS

The <audio> element has no intrinsic visual output of its own unless the controls attribute is specified, in which case the browser's default controls are shown.

The default controls have a display value of inline by default, and it is often a good idea set the value to block to improve control over positioning and layout, unless you want it to sit within a text block or similar.

You can style the default controls with properties that affect the block as a single unit, so for example you can give it a border and border-radius, padding, margin, etc. You can't however style the individual components inside the audio player (e.g. change the button size or icons, change the font, etc.), and the controls are different across the different browsers.

To get a consistent look and feel across browsers, you\'ll need to create custom controls; these can be marked up and styled in whatever way you want, and then JavaScript can be used along with the HTMLMediaElement API to wire up their functionality.

Video player styling basics provides some useful styling techniques --- it is written in the context of <video>, but much of it is equally applicable to <audio>.

Detecting addition and removal of tracks

You can detect when tracks are added to and removed from an <audio> element using the addtrack and removetrack events. However, these events aren't sent directly to the <audio> element itself. Instead, they\'re sent to the track list object within the <audio> element's HTMLMediaElement that corresponds to the type of track that was added to the element:

• HTMLMediaElement.audioTracks: An AudioTrackList containing all of the media element's audio tracks. You can add a listener for addtrack to this object to be alerted when new audio tracks are added to the element.

• HTMLMediaElement.videoTracks: Add an addtrack listener to this VideoTrackList object to be informed when video tracks are added to the element.

• HTMLElement.textTracks: Add an addtrack event listener to this TextTrackList to be notified when new text tracks are added to the element.

Note: Even though it's an <audio> element, it still has video and text track lists, and can in fact be used to present video, although the use interface implications can be odd.

For example, to detect when audio tracks are added to or removed from an <audio> element, you can use code like this:

var elem = document.querySelector("audio");

elem.audioTrackList.onaddtrack = function(event) {
  trackEditor.addTrack(event.track);
};

elem.audioTrackList.onremovetrack = function(event) {
  trackEditor.removeTrack(event.track);
};

This code watches for audio tracks to be added to and removed from the element, and calls a hypothetical function on a track editor to register and remove the track from the editor's list of available tracks.

You can also use addEventListener() to listen for the addtrack and removetrack events.

Audio with spoken dialog should provide both captions and transcripts that accurately describe its content. Captions allow people who are experiencing hearing loss to understand an audio recording's content as the recording is being played, while transcripts allow people who need additional time to be able to review the recording's content at a pace and format that is comfortable for them.

If automatic captioning services are used, it is important to review the generated content to ensure it accurately represents the source audio.

In addition to spoken dialog, subtitles and transcripts should also identify music and sound effects that communicate important information. This includes emotion and tone:

    1
    00:00:00 --> 00:00:45
    [Energetic techno music]

    2
    00:00:46 --> 00:00:51
    Welcome to the Time Keeper's podcast! In this episode we're discussing which Swisswatch is a wrist switchwatch?

    16
    00:00:52 --> 00:01:02
    [Laughing] Sorry! I mean, which wristwatch is a Swiss wristwatch?

• MDN Subtitles and closed caption --- Plugins
• Web Video Text Tracks Format (WebVTT)
• WebAIM: Captions, Transcripts, and Audio Descriptions
• MDN Understanding WCAG, Guideline 1.2 explanations
• Understanding Success Criterion 1.2.1 | W3C Understanding WCAG 2.0
• Understanding Success Criterion 1.2.2 | W3C Understanding WCAG 2.0

The following example shows simple usage of the <audio> element to play an OGG file. It will autoplay due to the autoplay attribute, and also includes fallback content.

This example specifies which audio track to embed using the src attribute on a nested <source> element rather than directly on the <audio> element. It is always useful to include the file's MIME type inside the type attribute, as the browser is able to instantly tell if it can play that file, and not waste time on it if not.

This example includes multiple <source> elements. The browser tries to load the first source element (Opus) if it is able to play it; if not it falls back to the second (Vorbis) and finally back to MP3.

• Media formats supported by the audio and video elements
• Web Audio API
• HTMLAudioElement
• nsIDOMHTMLMediaElement
• <source>
• <video>
• Using audio and video
• Cross-browser audio basics
• The audio element (HTML5 specification)