[Chrome Extension] Try to Print Facebook Id Next to User Name

{
  "manifest_version": 2,

  "name": "FBUrlId",
  "description" : "Try to get Facebook Id from URL change",
  "version": "0.1",

  "background": {
      "scripts": ["eventPage.js"]
  },

  "content_scripts": [
    {
      "matches": ["https://www.facebook.com/*"],
      "js": ["showid.js"]
    }
  ],

  "permissions": [
    "tabs"
  ]
}

var reId = /^https:\/\/www\.facebook\.com\/profile\.php\?id=(\d+)$/;
var reUser = /^https:\/\/www\.facebook\.com\/([a-zA-Z0-9.]+)$/;
var lastUrlIsId = false;

chrome.tabs.onUpdated.addListener(function(tabId, changeInfo, tab) {
  if (changeInfo.hasOwnProperty('url')) {

    //console.log(changeInfo.url);

    // check if URL consists of username
    var resultUser = changeInfo.url.match(reUser);
    if (resultUser) {
      //console.log(resultUser[1]); // username
      if (lastUrlIsId) {
        //console.log(resultUser[1] + " : " + id);
        chrome.tabs.query({active: true, currentWindow: true}, function(tabs) {
          chrome.tabs.sendMessage(tabs[0].id, {name: resultUser[1], id: id});
        });
      }
    }

    // check if URL consists of Id
    var resultId = changeInfo.url.match(reId);
    if (resultId) {
      //console.log(resultId[0]); // URL
      //console.log(resultId[1]); // id
      id = resultId[1];
      lastUrlIsId = true;
    } else {
      lastUrlIsId = false;
    }

  }
});

chrome.runtime.onMessage.addListener(
  function(request, sender, sendResponse) {
    //console.log(request.name);
    //console.log(request.id);

    // wait page to be loaded
    var timerId = setInterval(function() {
      var n = document.querySelector("#fb-timeline-cover-name");
      if (n != null) {
        var idNode = document.createTextNode(request.id);
        n.appendChild(idNode);
        clearInterval(timerId);
      }
    }, 500);
  });