timeupdate

Timeupdate is an event defined in the HTML5 media element API that fires on HTMLMediaElement instances such as HTMLVideoElement and HTMLAudioElement whenever the playback position changes, i.e., when the currentTime property updates. It is commonly used to refresh user interface elements that reflect playback progress, such as seek bars, time displays, and synchronized UI.

The exact frequency of timeupdate events is not guaranteed by the specification. They are emitted at the browser’s discretion, typically multiple times per second during playback and also when the user seeks to a new position. The event does not fire simply because the media is buffering; it fires as currentTime advances or after a seek finishes.

This event is part of the media element events set and is often used alongside play, pause, seeking, and seeked events. A common pattern is to attach a listener to update UI elements on timeupdate.

Example: var video = document.querySelector('video'); video.addEventListener('timeupdate', function() { console.log(this.currentTime); });

Browser support is broad across modern browsers, reflecting its role in updating playback-related interfaces. Timeupdate provides a lightweight mechanism to track progress without implementing a separate timer.

See also: durationchange, seeking, seeked, ended.