I'm developing an extension and I need to capture the selected text range.

This only can be done via window.getSelection() and doing messaging thru the extension and a content javascript loaded with all_frames = true in manifest.json

But content javascript only are loaded when the iframe has a src, not available with html editors like the one's used in hotmail, gmail and some forum boards.

This problem is some documented here and some techniques like js injection are mentioned but after implement them still cannot retrieve ranges.

Any ideas?