SourceBuffer: updatestart event

Note: This feature is available in Dedicated Web Workers.

The updatestart event of the SourceBuffer interface signals the beginning of an appendBuffer() or remove() operation. The updating attribute transitions from false to true.

Syntax

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

js

addEventListener("updatestart", (event) => { })

onupdatestart = (event) => { }

Event type

A generic Event.

Examples

undefined

Listening for the updatestart event

js

const sourceBuffer = source.addSourceBuffer(mimeCodec);
sourceBuffer.addEventListener("updatestart", () => {
  downloadStatus.textContent = "Modifying buffer...";
});
sourceBuffer.addEventListener("updateend", () => {
  downloadStatus.textContent = "Modification complete";
});

Specifications

See also