WordReference Translate w/o leaving the page

manifest.json

{
  "update_url": "https://clients2.google.com/service/update2/crx",
  "name": "__MSG_extensionName__",
  "version": "2.1.10",
  "description": "__MSG_extensionDescription__",
  "author": "__MSG_extensionAuthor__",
  "key": "MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAiPGWPKO0o6VJU/jaP0DrInQQSEgjS/zm5p5WuItZSk+/bQaj80Pa54E0/fjvdCAwEndSuu855RFmRwpzX8q4BN/FtGs2S5Dwg9UdF4ycH/LIG5q2ps/HTBPIqmLyZchmT9wrPYBAPYIOc75UXnSPs2RBDXQkryoU2BjSCwD7mQM0nEV7N7RXUfeQt0EMfko7tnnUXD96osUwpTl7BcOPWYHAanAUUdQslkjQSfnzW2+tsU3qH8IJCTGIH+lFDsqU69G7cynb7Gn870rm2BbxvbiZgmY8xI1DnWINhZLSAZhaG7auV66+iMNbHvlyYNovhoQy6bWfxAA6Tv+4E/SYbwIDAQAB",
  "manifest_version": 2,
  "default_locale": "en",
  "permissions": [
    "storage",
    "identity",
    "contextMenus",
    "https://diridevelops.altervista.org/wordreferencepopup/*",
    "https://www.wordreference.com/*"
  ],
  "optional_permissions": [
    "<all_urls>"
  ],
  "oauth2": {
    "client_id": "66388493183-bh980nmg050e439r2bhiprcf0nvnf2gg.apps.googleusercontent.com",
    "scopes": [
      ""
    ]
  },
  "background": {
    "page": "background.html",
    "persistent": false
  },
  "content_scripts": [
    {
      "matches": [
        "https://diridevelops.altervista.org/wordreferencepopup/login.php",
        "https://diridevelops.altervista.org/wordreferencepopup/paypal.php"
      ],
      "js": [
        "settings/userScript.js"
      ],
      "run_at": "document_end",
      "all_frames": true
    },
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "includes/jquery.min.js",
        "includes/globals.js",
        "popup/contentScript.js"
      ]
    }
  ],
  "web_accessible_resources": [
    "icons/*",
    "styles/*",
    "includes/jquery.min.js"
  ],
  "browser_action": {
    "default_popup": "popup/popup.html",
    "default_title": "__MSG_popTitle__",
    "default_icon": {
      "16": "icons/icon/icon-16.png",
      "32": "icons/icon/icon-32.png",
      "48": "icons/icon/icon-48.png",
      "96": "icons/icon/icon-96.png",
      "128": "icons/icon/icon-128.png"
    }
  },
  "options_ui": {
    "page": "settings/options.html",
    "open_in_tab": true
  },
  "icons": {
    "16": "icons/icon/icon-16.png",
    "32": "icons/icon/icon-32.png",
    "48": "icons/icon/icon-48.png",
    "96": "icons/icon/icon-96.png",
    "128": "icons/icon/icon-128.png"
  }
}