Question

I am trying to insert some extra code into the current tab page in chrome using an extension
i.e add a submit button on top of the page. Where does this go? and how would I initialize every page like this?

Answer 1

If you put this in your manifest.json,

"content_scripts": [{
  "matches": ["<all_urls>"],
  "js": ["example.js"],
  "css": ["example.css"]
}]

then example.js and example.css will be injected into every page you visit. See http://code.google.com/chrome/extensions/content_scripts.html for more information.