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index.md
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---
title: "HTMLMediaElement: loadstart event"
short-title: loadstart
slug: Web/API/HTMLMediaElement/loadstart_event
page-type: web-api-event
browser-compat: api.HTMLMediaElement.loadstart_event
---
{{APIRef}}
The **`loadstart`** event is fired when the browser has started to load a resource.
## Syntax
Use the event name in methods like {{domxref("EventTarget.addEventListener", "addEventListener()")}}, or set an event handler property.
```js
addEventListener("loadstart", (event) => {});
onloadstart = (event) => {};
```
## Event type
A generic {{domxref("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>
```
```css hidden
.event-log-contents {
width: 18rem;
height: 5rem;
border: 1px solid black;
margin: 0.2rem;
padding: 0.2rem;
}
.example {
display: grid;
grid-template-areas:
"button log"
"video log";
}
button {
grid-area: button;
width: 10rem;
margin: 0.5rem 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 += `${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/cc0-videos/flower.webm",
);
source.setAttribute("type", "video/webm");
video.appendChild(source);
}
});
```
#### Result
{{ EmbedLiveSample('Live_example', '100%', '200px') }}
## Specifications
{{Specifications}}
## Browser compatibility
{{Compat}}
## See also
- {{domxref("HTMLAudioElement")}}
- {{domxref("HTMLVideoElement")}}
- {{HTMLElement("audio")}}
- {{HTMLElement("video")}}