The durationchange event is fired when the duration attribute has been updated.

Use the event name in methods like addEventListener(), or set an event handler property.

addEventListener("durationchange", (event) => {});

ondurationchange = (event) => {};

A generic Event.

These examples add an event listener for the HTMLMediaElement's durationchange event, then post a message when that event handler has reacted to the event firing.

Using addEventListener():

const video = document.querySelector("video");

video.addEventListener("durationchange", (event) => {
  console.log("Not sure why, but the duration of the video has changed.");
});

Using the ondurationchange event handler property:

const video = document.querySelector("video");

video.ondurationchange = (event) => {
  console.log("Not sure why, but the duration of the video has changed.");
};

• The HTMLMediaElement playing event
• The HTMLMediaElement waiting event
• The HTMLMediaElement seeking event
• The HTMLMediaElement seeked event
• The HTMLMediaElement ended event
• The HTMLMediaElement loadedmetadata event
• The HTMLMediaElement loadeddata event
• The HTMLMediaElement canplay event
• The HTMLMediaElement canplaythrough event
• The HTMLMediaElement durationchange event
• The HTMLMediaElement timeupdate event
• The HTMLMediaElement play event
• The HTMLMediaElement pause event
• The HTMLMediaElement ratechange event
• The HTMLMediaElement volumechange event
• The HTMLMediaElement suspend event
• The HTMLMediaElement emptied event
• The HTMLMediaElement stalled event

• HTMLAudioElement
• HTMLVideoElement
• <audio>
• <video>