HTMLMediaElement: progress event

progress 事件在浏览器加载一个资源的时候周期性触发。

Bubbles No
Cancelable No
Interface Event
Event handler property onprogress

示例

HTML

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

  <div class="event-log">
    <label>Event log:</label>
    <textarea readonly class="event-log-contents"></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 = 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://mdn.github.io/learning-area/html/multimedia-and-embedding/video-and-audio-content/rabbit320.mp4",
    );
    source.setAttribute("type", "video/mp4");

    video.appendChild(source);
  }
});

结果

规范

Specification
HTML Standard
# event-media-progress
HTML Standard
# handler-onprogress

浏览器兼容性

BCD tables only load in the browser

参见