使用URL将URL重定向到子域

I wanted to redirect https://www.domain.rs to https://mysite.domain.rs AND https://www.mysite.rs/this_is_some_page.html to https://mysite.domain.rs/this_is_some_page.html... How can I do it?

I have tried this:

RewriteEngine On
RewriteCond %{HTTP_HOST} ^(www.)?mysite\.rs$ [NC]
RewriteRule ^(.*)$ https://mysite.domain.rs/ [L,R=302]

But this only redirects me to https://mysite.domain.rs regardless of what U. R. L. continues after the /. I wanted it to be redirected to whatever U. R. L. is entered as https://www.domain.rs/this_is_my_page.php to https://mysite.domain.rs/this_is_my_page.php

Any help?

This line :

RewriteRule ^(.*)$ https://mysite.domain.rs/ [L,R=302]

Should be :

RewriteRule ^(.*)$ https://mysite.domain.rs/$1 [L,R=302]

This pasrt ^(.*)$ pattren(Regex) is to match against the URI of the current request and the substitution https://mysite.domain.rs/$1 is the location you want rewrite to so , this regex ^(.*)$ will be presented by $1.

Clear browser cache then test if every thing is Ok , change [L,R=302] to [L,R=301] to be permenant redirection .