Apply a Greasemonkey/Tampermonkey/userscript to an iframe?

Question

The title is pretty much the question:

Is it possible to add a Greasemonkey script to an iframed website?

If so, how?

Thank you.

Answer 1

Note that if you're making a chrome extension for your userscript, you also need to add "all_frames": true to your manifest or your extension won't work on iframes.

Example from manifest file:

"content_scripts": [
    {
      "matches": ["*://*/*"],
      "all_frames": true,
      "js":["dont.js"],
      "run_at":"document_start"
    }
  ]

Example use case: https://github.com/NavinF/dont