Worklet
Baseline
Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since April 2021.
Secure context: This feature is available only in secure contexts (HTTPS), in some or all supporting browsers.
The Worklet interface is a lightweight version of Web Workers and gives developers access to low-level parts of the rendering pipeline.
With Worklets, you can run JavaScript and WebAssembly code to do graphics rendering or audio processing where high performance is required.
Worklets allow static import of ECMAScript modules, if supported, using import.
Dynamic import is disallowed by the specification — calling import() will throw.
Worklet types
Worklets are restricted to specific use cases; they cannot be used for arbitrary computations like Web Workers. The Worklet interface abstracts properties and methods common to all kind of worklets, and cannot be created directly. Instead, you can use one of the following classes:
| Name | Description | Location | Specification |
|---|---|---|---|
AudioWorklet |
For audio processing with custom AudioNodes. | Web Audio render thread | Web Audio API |
AnimationWorklet |
For creating scroll-linked and other high performance procedural animations. | Compositor thread | CSS Animation Worklet API |
LayoutWorklet |
For defining the positioning and dimensions of custom elements. | CSS Layout API | |
SharedStorageWorklet |
For running private operations on cross-site data, without risk of data leakage. | Main thread | Shared Storage API |
Note:
Paint worklets, defined by the CSS Painting API, don't subclass Worklet. They are accessed through a regular Worklet object obtained using CSS.paintWorklet.
For 3D rendering with WebGL, you don't use worklets. Instead, you write vertex shaders and fragment shaders using GLSL code, and those shaders will then run on the graphics card.
Instance properties
The Worklet interface does not define any properties.
Instance methods
Worklet.addModule()-
Adds the script module at the given URL to the current worklet.
Specifications
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| HTML # worklets-worklet |
Browser compatibility
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Worklet
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addModule
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Support for ECMAScript modules
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Legend
Tip: you can click/tap on a cell for more information.
- Full support
- Full support
- See implementation notes.
See also
- Houdini: Demystifying CSS on Google Developers (2016)
- AudioWorklet :: What, Why, and How on YouTube (2017)
- Enter AudioWorklet on Google Developers (2017)
- Animation Worklet - HTTP203 Advent on YouTube (2017)