This documentation provides a technical deep dive into Blink’s JavaScript execution pipeline, explaining how Chromium orchestrates the transition from HTML parsing to code evaluation. It details the roles of essential C++ classes like HTMLScriptElement and ScriptLoader, which manage the fetching and lifecycle of both inline and external scripts. The text explains how the ScriptRunner schedules execution tasks based on attributes like async and defer, ensuring the browser remains responsive while respecting web standards. Furthermore, it examines the integration with the V8 engine through the ScriptController, which handles the final compilation and execution of scripts within specific security contexts. Security is a central theme, highlighting how Content Security Policy and sandboxing are enforced throughout the loading process to protect the user environment. Ultimately, the source illustrates the complex coordination between multithreaded resource fetching, DOM manipulation, and the JavaScript runtime.