manifest.json

{
  "name": "Test",
  "version": "1.0",
  "manifest_version": 2,
  "description": "The first extension that I made.",
  "_browser_action": {
    "default_popup": "popup.html"
  },
  "background": {"scripts":["bg.js"]},
  "permissions": ["webRequest", "webRequestBlocking",
                  "http://www.altavista.com/*",
                  "http://*.google.com/*",
                  "https://*.google.com/*"]
}