e621/926 next/prev post shortcut

manifest.json

{
  "manifest_version": 2,
  "name": "e621.net shortcuts",
  "version": "1.3",
  "description": "Go to next post and prev post.",
  "content_scripts": [
    {
      "matches": [
        "*://e621.net/*",
        "*://e926.net/*"
      ],
      "js": [
        "ext.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{a584d42e-b69a-413a-af9f-41784be24a37}"
    }
  }
}