How to inject Javascript at runtime in Chronium?

[Jonathan Urban]

Hi Team,

We have an extension that is running in background and in content_script on every pages .

We would like to inject additional Javascript code in c++ at runtime (e.g. alert('Hello World!');), just after the execution of the extension js scripts.

After a lot of hours of chromium code browsing and tests, we didn't found the right place where loaded extension js script are injected and executed in pages.

We just find the place where extension js script are loaded into shared_memory:

https://source.chromium.org/chromium/chromium/src/+/main:extensions/browser/user_script_loader.cc;l=348?q=UserScriptLoader::Serialize&ss=chromium%2Fchromium%2Fsrc

Could you indicate where could be the best place to inject additional JS code, please ?

Many thanks four your help!

Jonathan.