# Gitbook Plugin `noopener`

This extension adds `rel="noopener noreferrer" to any links which are external links or defined with target '_blank'. This improves the security of the site:

- **noopener**: Instructs the browser to open the link without granting the new browsing context access to the document that opened it — by not setting the Window.opener property on the opened window (it returns null).
- **noreferrer**: Prevents the browser, when navigating to another page, to send this page address, or any other value, as referrer via the `Referer:` HTTP header.

## Installation

Add the plugin to your `book.json`:

```
{
	"plugins" : [ "noopener" ]
}		
```