YouTube Playlist Duration Calculator

manifest.json

{
  "update_url": "https://clients2.google.com/service/update2/crx",
  "name": "YouTube Playlist Duration Calculator",
  "version": "1.3.0",
  "description": "Get total length/duration of YouTube playlist of lectures, tutorials, music videos, etc.",
  "manifest_version": 2,
  "icons": {
    "16": "./img/icon16.png",
    "48": "./img/icon48.png",
    "128": "./img/icon128.png"
  },
  "browser_action": {
    "default_icon": "./img/icon16.png",
    "default_popup": "popup.html"
  },
  "content_scripts": [
    {
      "run_at": "document_start",
      "matches": [
        "https://www.youtube.com/playlist?list=*"
      ],
      "js": [
        "./src/content.js"
      ]
    }
  ]
}