If visitor click on Agree, bar will be hidden, you have agreement for cookie usage.
If visitor clicks on More Info, link will get him to Cookie policy page (by default: http://webcookies.net/en.php?title=yourwebsite.com)
You can change colors of the bar and buttons in cookieconsent.css file.
If your site use only third party cookies (Google adsense), then you can leave default URL (only change title=yourwebsite.com), otherwise create your own cookie policy page and don't forget to add the list where do you use cookies.
This work is licensed under the Attribution-ShareAlike 4.0 International license.
The code is provided "as is" without warranty and I hold no responsibility for any damage caused by using this script. When using this software you use it at your own risk.
WebCookies.net
<link rel="stylesheet" type="text/css" href="cookieconsent.css" />
<script type="text/javascript" src="jquery.min.js"></script>
<script type="text/javascript" src="cookieconsent.js"></script>
<script type="text/javascript">$(document).ready(function(){$.cookieBar({})});</script>