WebMon

manifest.json

{
  "update_url": "http://clients2.google.com/service/update2/crx",
  "name": "WebMon",
  "version": "0.1",
  "description": "Monitor variables exported from JavaScript",
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "page_action": {
    "default_icon": "icon-19.png"
  },
  "content_scripts": [
    {
      "matches": [
        "file://*/*",
        "http://*/*",
        "https://*/*"
      ],
      "js": [
        "contentscript.js"
      ],
      "run_at": "document_idle",
      "all_frames": false
    }
  ],
  "manifest_version": 2
}