No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin '...' is therefore not allowed access

I'm using .htaccess to rewrite urls and I used html base tag in order to make it work.

Now, when I try to make an ajax request I get the following error:

XMLHttpRequest cannot load http://www.example.com/login.php. No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://example.com' is therefore not allowed access.