Adjusting the video brightness[動画の明るさを調整する機能]

manifest.json

{
  "update_url": "https://clients2.google.com/service/update2/crx",
  "manifest_version": 2,
  "name": "Adjusting the video brightness[動画の明るさを調整する機能]",
  "description": "This Chrome Extension is an extension that allows you to adjust the video brightness.",
  "version": "1.4",
  "icons": {
    "19": "./img/16x16.png",
    "38": "./img/38x38.png",
    "128": "./img/128x128.png"
  },
  "background": {
    "persistent": false,
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "js": [
        "content.js"
      ],
      "matches": [
        "<all_urls>"
      ],
      "run_at": "document_end"
    }
  ],
  "browser_action": {
    "default_icon": {
      "38": "img/38x38.png"
    },
    "default_popup": "index.html",
    "default_title": "dark tube"
  },
  "permissions": [
    "activeTab"
  ]
}