On-the-fly javascript interception : solving the sandbox problem.
Use case: Should your extension require to interact with the current page in a very intimate fashion (and there are opportunities for this...) , you may encounter the roadblock of the javascript sandboxing: javascript code and data are confined in different contexts. Your content script will therefore not be able to access the JS legitimately imported by the page. Solution: In order to gain access and interact with the data and code available in the page, the solution is to insert a proxy javascript snippet in the page. But you can't do this by simply adding a script tag. Instead, you will need to: Design a proxy script based on a window event listener Identify the script you need to deal with (using browser debugging tools such as chrome devtools) Intercept the targetted script at load time and modify it. Send commands thru event messages to your proxy which HAVE access. Implementation: 1/ Proxy var proxyCode = `window.addEventListener('message',