Wordpress为/ wp-content / themes中的所有文件设置了Access-Control-Allow-Origin

I'm having a lot of problems with CORS errors. So I want to set header("Access-Control-Allow-Origin: *") for everything in my WordPress wp-content/themes directory.

I tried to add it to the .htaccess in /var/www/html but this isn't working in /wp-content

Anyone has an idea on how to do this in a WordPress install?

EDIT: It's a self-hosted ubuntu 14.04 server. And the problem arises with static files, so I cannot add the access control to the header function.

EDIT2:

I think I didn't explain the situation correct.

I have a page on my Wordpress site get10things.com this site uses scripts which loads resources from the same domain. However I want to show parts of this site in iframes on other domains and in our Android and iOS app. Therefor I need to enable "Access-Control-Allow-Origin: *" on all resources which are loaded in the scripts which are used on get10things.com.