By implementing the 'X XSS Protection header' you can prevent a degree of 'cross site scripting' (XSS) attacks. It's another easy security header to implement and is widely utilised by all of the huge sites such as Github, Facebook and Google.
The below snippet of htaccess code will enable the XSS filter and add another layer of security to your site:
Header set X-XSS-Protection "1; mode=block"
All security policies can be contained in the one .htaccess 'Ifmodule' tag like the below example that has 3 rules in it:
Header set X-XSS-Protection "1; mode=block"
Header set X-Frame-Options "sameorigin"
Header set X-Content-Type-Options "nosniff"