Loading scripts only on single.php

Hi! Firstly, thank you for a great plugin!

How ever, I would like to load scripts only where needed; this case on single.php, where comments are.
I was able to do this on main site with <?php if (is_single()) { ?> -rule in the header, (I know, that’s not the most best way to do it), and all works fine. But with subdomains this does not work fully, cause I’m out of ideas, how to link correctly plugins ajaxurl.

Any help would be really appreciated.

https://wordpress.org/plugins/safe-report-comments/