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---
title: 'HTMLMediaElement: progress event'
slug: Web/API/HTMLMediaElement/progress_event
tags:
- API
- Event
- HTMLMediaElement
- Reference
- Web
- progress
translation_of: Web/API/HTMLMediaElement/progress_event
---
{{APIRef}}
**`progress`** 事件在浏览器加载一个资源的时候周期性触发。
<table class="properties">
<tbody>
<tr>
<th scope="row">Bubbles</th>
<td>No</td>
</tr>
<tr>
<th scope="row">Cancelable</th>
<td>No</td>
</tr>
<tr>
<th scope="row">Interface</th>
<td>{{domxref("Event")}}</td>
</tr>
<tr>
<th scope="row">Event handler property</th>
<td><code>onprogress</code></td>
</tr>
</tbody>
</table>
## 示例
### 在线示例
#### 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>
```
```css hidden
.event-log-contents {
width: 18rem;
height: 5rem;
border: 1px solid black;
margin: .2rem;
padding: .2rem;
}
.example {
display: grid;
grid-template-areas:
"button log"
"video log";
}
button {
grid-area: button;
width: 10rem;
margin: .5rem 0;
}
video {
grid-area: video;
}
.event-log {
grid-area: log;
}
.event-log>label {
display: block;
}
```
#### 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
{{ EmbedLiveSample('Live_example', '100%', '250px') }}
## 规范
{{Specifications}}
## 浏览器兼容性
{{Compat}}
## 参见
- {{domxref("HTMLAudioElement")}}
- {{domxref("HTMLVideoElement")}}
- {{HTMLElement("audio")}}
- {{HTMLElement("video")}}
|
