Can I apply Javascript to pages through frames?

This is some-more only curiosity. But is it probable to request javascripts to pages which have been being displayed in frames? Kind of similar to how Greasemonkey relates javascript to pages displayed in a browser. Basically so which no make a difference who visited a web page, either they had Greasemonkey or not, they would be means to see a web page with my law javascripts applied. If this is possible, how would we go about you do it?