HTMLMediaElement: loadstart event

This translation is incomplete. Please help translate this article from English

loadstart 事件当浏览器开始载入一个资源文件时fired.

Bubbles No
可撤销 No
Interface Event
Event handler property onloadstart

Examples

Live example

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>

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://interactive-examples.mdn.mozilla.net/media/examples/flower.webm');
        source.setAttribute('type', 'video/webm');

        video.appendChild(source);
    }
});

Result

Specifications

Specification Status
HTML Living Standard
loadstart media event
Living Standard
HTML5
loadstart media event
Recommendation

Browser compatibility

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
loadstart eventChrome Full support YesEdge ? Firefox Full support YesIE ? Opera Full support YesSafari ? WebView Android Full support YesChrome Android Full support YesFirefox Android Full support YesOpera Android ? Safari iOS ? Samsung Internet Android Full support Yes

Legend

Full support  
Full support
Compatibility unknown  
Compatibility unknown

See also