webextension tab url

manifest.json

{
  "manifest_version": 2,

  "name": "Tab url",
  "description": "Shows url of the current page",
  "version": "1.0",

  "browser_action": {
    "default_icon": "icon.png",
    "default_popup": "popup.html"
  },
  "permissions": [
    "tabs"
  ]
}

popup.html

<div id="info"></div>
<script src="popup.js"></script>

popup.js

var queryInfo = {
  active: true,
  lastFocusedWindow: true
}

chrome.tabs.query(queryInfo, function (tabs) {
    var url = tabs[0].url;
    info.textContent = url
});