How to set up CORS (cross-origin resource sharing) in Plesk?

Question

How to set up cross-origin resource sharing (CORS) in Plesk to display content from example1.com on example.com ?

Answer

On the source server where domain example1.com is hosted, go to Domains > example1.com > Apache and nginx settings and add the following directives in Additional directives for HTTP and Additional directives for HTTPS:

CONFIG_TEXT: Header set Access-Control-Allow-Origin "example.com"

Alternatively, in this case .htaccess file with the following content can be used:

CONFIG_TEXT: <IfModule mod_headers.c>
Header always set Access-Control-Allow-Origin "example.com"
</IfModule>

If nginx is enabled and static content needed to be displayed, additionally add the following directive to Additional nginx directives field:

CONFIG_TEXT: add_header Access-Control-Allow-Origin "example.com";

Note: CORS is supported in the following browsers:
Chrome 3+
Firefox 3.5+
Opera 12+
Safari 4+
Internet Explorer 8+

To learn more about implementing CORS for a specific platform check Enable CORS website