Frontend & browser·JavaScript in the browser
you moved the parsing off to another thread and the interface kept responding while it ran.
Web worker
Also calledworker thread, dedicated worker
A separate thread running a script with no access to the DOM, communicating with the page by message passing. It is the only real answer to CPU-bound work in the browser, and it is under-used because the boundary is awkward: everything crossing it is structured-cloned, which for large objects can cost more than the work saved. Anything touching the DOM has to come back to the main thread, so workers suit computation, not rendering.