Why is script.onload not working in a Chrome userscript?

Question

I want to load another script file, in a site, using a userscript. But, the js.onload event doesn\'t work correctly.

The userscript file:

Answer 1

Never use .onload, .onclick, etc. from a userscript. (It's also poor practice in a regular web page).

The reason is that userscripts operate in a sandbox ("isolated world"), and you cannot set or use page-scope javascript objects in a Chrome userscript or content-script.

Always use addEventListener() (or an equivalent library function, like jQuery .on()). Also, you should set load listeners before adding