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Happy DOM is a JavaScript implementation of a web browser without its graphical user interface. It includes many web standards from WHATWG DOM and HTML.

The goal of Happy DOM is to emulate enough of a web browser to be useful for testing, scraping web sites and server-side rendering.

Happy DOM focuses heavily on performance and can be used as an alternative to JSDOM.

DOM Features

Custom Elements (Web Components)
Declarative Shadow DOM
Mutation Observer
Tree Walker
Fetch API
File Reader
CSS Style Declaration
Form Data
Selection
Form Validity State
IFrames
Cookies
Clipboard

And much more..

Browser Features

Other Features

Server-Side Rendering

Performance

Operation	JSDOM	Happy DOM
Import / Require	333 ms	45 ms
Parse HTML	256 ms	26 ms
Serialize HTML	65 ms	8 ms
Render custom element	214 ms	19 ms
querySelectorAll('tagname')	4.9 ms	0.7 ms
querySelectorAll(':nth-child(2n+1)')	10.4 ms	3.8 ms