Simple Chrome extension: show a counter from API

I already talked about my game "Blind Friends" (which also exists on Windows Phone)...

The game was not a great success but the number of registered players in my database increases progressively.
I had already created a simple action that sends the number of registered players (in JSON: so I can add more information if I need it):

   1:  public JsonResult playercount()

   2:  {

   3:      return Json(new { Count = Db.GetCountPlayers() }, JsonRequestBehavior.AllowGet);

   4:  }

At the beginning, I was checking that number at the URL corresponding to the action in my web app... But it was not very convenient... So I decided to create a small extension for Chrome:

The code is very simple: I just need to check an URL every two minutes.
The extension contains 4 files:

• background.js
• icon.png (I took the favicon of my web app)
• jquery.js (a local copy of a recent version of Jquery)
• manifest.json

Code of background.js:

   1:  var pollInterval = 2;  // 2 minutes

   2:   

   3:  function updateCounter() {

   4:      $.getJSON('{the url which returns a json with a "Count" property...}', function(json) {

   5:          chrome.browserAction.setBadgeText({

   6:              text: json.Count.toString()

   7:          });

   8:      });

   9:  }

  10:   

  11:  $(document).ready(function () {

  12:      updateCounter(); // we call the function one time here because

  13:                       // the alarm will be triggered one minute after

  14:   

  15:      chrome.browserAction.setBadgeBackgroundColor({

  16:          color: "#000"

  17:      })

  18:          

  19:      chrome.alarms.onAlarm.addListener(function (alarm) {

  20:          updateCounter();

  21:      });

  22:          

  23:      chrome.alarms.create('blindFriendsAlarm', {periodInMinutes: pollInterval});

  24:  })

Code of manifest.json:

   1:  {

   2:    "manifest_version": 2,

   3:   

   4:    "name": "Blind Friends Counter",

   5:    "description": "Count the number of Blind Friends users.",

   6:    "version": "1.0",

   7:   

   8:    "permissions": [

   9:      "https://www.blindfriendsthegame.com/",

  10:      "alarms"

  11:    ],

  12:    "browser_action": {

  13:      "default_icon": "icon.png"

  14:    },

  15:    "background": {

  16:      "scripts": ["jquery.js", "background.js"],

  17:      "persistent": false

  18:    }

  19:  }

The installation is simple: you have to click on "Load unpacked extension" in the extensions page of Chrome

And you just have to select the folder which contains the previous files...