SolinariWu/manifest.json

## manifest.json
{
  "manifest_version": 2,
  "name": "Google extensions easy sample",
  "description": "Show current page URL",
  "version": "1.0",
  "browser_action": {
   "default_icon":"icon.png" ,
   "default_popup": "popup.html"
  },
  "permissions": ["tabs"]
}

## popup.css
/*
File:popup.css
Author:SolinariWu
Descript:Google Extensions Easy Sample-Show current page URL
Date:2016/7/25
Reference:https://developer.chrome.com/extensions
          http://www.cnblogs.com/guogangj/p/3235703.html
*/
body {
	width: 200px;
}

## popup.html
<!--
File:popup.html
Author:SolinariWu
Descript:Google Extensions Easy Sample-Show current page URL
Date:2016/7/25
Reference:https://developer.chrome.com/extensions
          http://www.cnblogs.com/guogangj/p/3235703.html
-->
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Google Extensions Easy Sample</title>
<link rel="stylesheet" type="text/css" href="popup.css" />
</head>
<body>
<div id = "msgLabel" ">Show URL</div>
</body>
<script src="jquery-3.1.0.min.js"></script>
<script src="popup.js"></script>
</html>

## popup.js
/*
File:popup.html
Author:SolinariWu
Descript:Google Extensions Easy Sample-Show current page URL
Date:2016/7/25
Reference:http://www.cnblogs.com/guogangj/p/3235703.html
          https://developer.chrome.com/extensions
*/
document.addEventListener('DOMContentLoaded', function () {
	chrome.tabs.query({'active': true, 'lastFocusedWindow': true}, function (tabs) {
    var url = tabs[0].url;
    $("#msgLabel").text(url);
    });
});
	{
	"manifest_version": 2,
	"name": "Google extensions easy sample",
	"description": "Show current page URL",
	"version": "1.0",
	"browser_action": {
	"default_icon":"icon.png" ,
	"default_popup": "popup.html"
	},
	"permissions": ["tabs"]
	}