Running content script after page load not working

Add-ons Development
#1 
//content_script.js
(function() {
    window.addEventListener('load', function() {
       console.log('here');
    });
})();

As simple as that, I want my content script do something after the page fully loaded, but I cannot even receive a log call

#2

I can’t answer your question.
But I have two questions of my own:

  1. Why are you using an https://en.wikipedia.org/wiki/Immediately_invoked_function_expression
  1. Why are you using window.addEventListener(‘load’, …)
    instead of https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/content_scripts#run_at

edit:
“run_at”: “document_idle” isn’t even necessary, because that’s the default.

#3

why not?

Additional text to let me post my answer, sicne it has to be 20 characters.

#4

Possibly the event already occurred at the time your content script runs. Perhaps check the following property first and only create a listener if the document is still loading:

#5

It was just a missing semicolon ¬_¬