Show protocol of address

manifest.json

{
  "update_url": "https://clients2.google.com/service/update2/crx",
  "name": "Show protocol of address",
  "version": "0.0.1",
  "manifest_version": 2,
  "description": "Display protocol (https, http, ftp, ...) from given web address",
  "icons": {
    "16": "icons/icon-16.png",
    "128": "icons/icon-128.png"
  },
  "default_locale": "en",
  "background": {
    "scripts": [
      "scripts/background.js"
    ]
  },
  "permissions": [
    "tabs",
    "storage",
    "http://*/*",
    "https://*/*",
    "webRequest",
    "webNavigation"
  ],
  "content_scripts": [
    {
      "matches": [
        "*://*/*"
      ],
      "js": [
        "scripts/contentscript.js"
      ]
    }
  ],
  "browser_action": {
    "default_icon": {
      "19": "icons/icon-19.png",
      "38": "icons/icon-38.png"
    }
  }
}