Period Formed By Double Space

manifest.json

{
  "update_url": "https://clients2.google.com/service/update2/crx",
  "manifest_version": 2,
  "name": "Period Formed By Double Space",
  "description": "This extension turns double spaces into period and space.",
  "version": "1.0.8",
  "author": "Tomasz Oleksik",
  "icons": {
    "16": "resources/icon_16x16.png",
    "32": "resources/icon_32x32.png",
    "48": "resources/icon_48x48.png",
    "128": "resources/icon_128x128.png"
  },
  "browser_action": {
    "default_popup": "popup.html",
    "default_title": "Double space make period"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "./contentscript.js"
      ]
    }
  ]
}