DEDICATED WORKERS

A dedicated worker is the simplest type of web worker. Dedicated workers are created by a web page to execute scripts outside the page's thread of execution. These workers are capable of exchanging information with the parent page, sending network requests, performing file I/O, executing intense computation, processing data in bulk, or any other number of computational tasks that are unsuited for the page execution thread (where they would introduce latency issues).

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NOTE   When dealing with workers, where a script is executing and where it was loaded from are important concepts. Unless otherwise specified, assume throughout this chapter that main.js is a top-level script loaded from and executing on the root path of the https://example.com domain.

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Dedicated Worker Basics

Dedicated workers can be aptly described as background scripts. The characteristics of a JavaScript worker—including lifecycle management, code path, and input/output...