https://developers.google.com/+/web/+1button/ You can add and customize the +1 button to meet the needs of your website, such as modifying the button size and load technique. By adding the +1 button to your website, you allow your users to recommend your content to their circles and drive traffic to your site. The +1 button can also improve the time spent on your site by providing recommendations for further reading.
A Simple Button
The script must be loaded from the HTTPS protocol and can be included from any point on the page without restriction.