manifest.json

{
   "manifest_version": 2,
   "name": "ironman6",
   "version": "1.0",
   "browser_action": {  
      "default_popup": "index.html"  
   },
   "permissions": [
      "notifications"
   ]
}

index.html

        <title>ironman6</title>
        <style>body {width: 500px;}</style> 
    
    
    	<button id="showNotifier">Show Notification</button>
        <script src="app.js"></script>
    

app.js

document.querySelector("#showNotifier").addEventListener("click", showNotifier);

function showNotifier(){
	var Notifier = webkitNotifications.createNotification(
		'chrome://extension-icon/',
		'Ironman6',
		'Day 13'
	);
	Notifier.show();
}