manifest.json

{

  "description": "If we click button inside popup then etxt from api is update in dom with that id currently id is comment",
  "manifest_version": 2,
  "name": "Add Text From Extension",
  "version": "1.0",
  "homepage_url": "https://github.com/mdn/webextensions-examples/tree/master/beastify",
  "icons": {
    "48": "icons/beasts-48.png"
  },

  "permissions": [
    "notifications",
        "activeTab",
        "webRequest",
        "<all_urls>"
  ],

  "browser_action": {
    "default_icon": "icons/beasts-32.png",
    "theme_icons": [{
        "light": "icons/beasts-32.png",
        "dark": "icons/beasts-32.png",
        "size": 32
    }],
    "default_title": "Click to add text in textarea",
    "default_popup": "popup/choose_beast.html"
  },

  "web_accessible_resources": [
    "beasts/*.jpg"
  ],
  "content_scripts":[
    {
        "matches": ["*://*.localhost/*","<all_urls>"],
        "js": ["popup/browser-polyfill.js","/content_scripts/beastify.js"]
    }
]

}