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HTMLMediaElement: loadstart event

The loadstart event is fired when the browser has started to load a resource.

Syntax

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

js

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

onloadstart = (event) => {};

Event type

A generic Event.

Examples

Live example

HTML

html

<div class="example">
  <button type="button">Load video</button>
  <video controls width="250"></video>

  <div class="event-log">
    <label for="eventLog">Event log:</label>
    <textarea readonly class="event-log-contents" id="eventLog"></textarea>
  </div>
</div>

JavaScript

js

const loadVideo = document.querySelector("button");
const video = document.querySelector("video");
const eventLog = document.querySelector(".event-log-contents");
let source = null;

function handleEvent(event) {
  eventLog.textContent += `${event.type}\n`;
}

video.addEventListener("loadstart", handleEvent);
video.addEventListener("progress", handleEvent);
video.addEventListener("canplay", handleEvent);
video.addEventListener("canplaythrough", handleEvent);

loadVideo.addEventListener("click", () => {
  if (source) {
    document.location.reload();
  } else {
    loadVideo.textContent = "Reset example";
    source = document.createElement("source");
    source.setAttribute(
      "src",
      "https://interactive-examples.mdn.mozilla.net/media/examples/flower.webm",
    );
    source.setAttribute("type", "video/webm");

    video.appendChild(source);
  }
});

Result

Specifications

Browser compatibility

Desktop Mobile
Chrome Edge Firefox Internet Explorer Opera Safari WebView Android Chrome Android Firefox for Android Opera Android Safari on IOS Samsung Internet
loadstart_event 3 12 6 9 ≤12.1 4 4.4 18 6 ≤12.1 3 1.0

See also

© 2005–2023 MDN contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/API/HTMLMediaElement/loadstart_event