TaskPriorityChangeEvent: TaskPriorityChangeEvent() constructor

Limited availability

This feature is not Baseline because it does not work in some of the most widely-used browsers.

Note: This feature is available in Web Workers.

The TaskPriorityChangeEvent() constructor creates a new TaskPriorityChangeEvent object.

This object is created with a value indicating the previous priority of the task: the priority before it changed and this event was fired.

Syntax

js
new TaskPriorityChangeEvent(type, options)

Parameters

type

A string with the case-sensitive name of the associated event. User agents set it to "prioritychange".

options

An object that, in addition of the properties defined in Event(), can have the following properties:

previousPriority

A string indicating the previous priority of the task. One of: "user-blocking", "user-visible", "background".

Specifications

Specification
Prioritized Task Scheduling
# dom-taskprioritychangeevent-taskprioritychangeevent

Browser compatibility

desktop mobile
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
WebView on iOS
TaskPriorityChangeEvent() constructor
Chrome – Full support
Chrome 94 (Release date: 2021-09-21)
footnote Full support
Edge – Full support
Edge 94 (Release date: 2021-09-24)
footnote Full support
Firefox – Full support
Firefox 142 (Release date: 2025-08-19)
footnote Full support
Opera – Full support
Opera 80 (Release date: 2021-10-05)
footnote Full support
Safari – No support
Safari
footnote No support
Chrome Android – Full support
Chrome Android 94 (Release date: 2021-09-21)
footnote Full support
Firefox for Android – Full support
Firefox for Android 142 (Release date: 2025-08-19)
footnote Full support
Opera Android – Full support
Opera Android 66 (Release date: 2021-12-15)
footnote Full support
Safari on iOS – No support
Safari on iOS
footnote No support
Samsung Internet – Full support
Samsung Internet 17 (Release date: 2022-05-04)
footnote Full support
WebView Android – Full support
WebView Android 94 (Release date: 2021-09-21)
footnote Full support
WebView on iOS – No support
WebView on iOS
footnote No support

Legend

Tip: you can click/tap on a cell for more information.

Full support
Full support
No support
No support