select and convert to markdown

manifest.json

{
  "update_url": "https://clients2.google.com/service/update2/crx",
  "name": "select and convert to markdown",
  "version": "0.1.0",
  "manifest_version": 2,
  "description": "Copy select text and convert to Markdown code",
  "permissions": [
    "tabs",
    "contextMenus",
    "http://*/*",
    "https://*/*"
  ],
  "icons": {
    "16": "toolbar-copy-convert-markdown.png",
    "48": "toolbar-copy-convert-markdown.png",
    "128": "toolbar-copy-convert-markdown.png"
  },
  "background": {
    "page": "background.html"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "all_frames": false,
      "js": [
        "content_script.js"
      ]
    }
  ]
}