Non-Intrusive JavaScript Runtime Instrumentation via Chrome DevTools Protocol for Advanced Debugging and Reverse Engineering

Introduction In contemporary web development, debugging and reverse engineering JavaScript applications often resemble navigating a complex, opaque system where critical vulnerabilities or performance bottlenecks can remain elusive. Traditional debugging techniques—such as source code modification, logging, or browser breakpoints—prove inadequate, particularly when confronted with minified, obfuscated, or dynamically generated code. Here, non-intrusive JavaScript runtime instrumentation emerges as a transformative solution, with the Chrome DevTools Protocol (CDP) serving as its foundational technology. CDP enables the interception and manipulation of function execution flows, inspection of arguments, and modification of behavior or return values, all without altering the application’s original codebase. This capability mirrors the revolutionary impact of tools like Frida, which introduced onEnter/onLeave handlers for native application debugging. By extending such functionality to the