PHP string check: Russian letters and space only

Help me write regular expressions to check the string: it should contain only Russian letters and spaces.

Answer 1, authority 100%


Answer 2

If you don’t want to be allowed in the post, do – check before sending. Regular expressions + javascript. Before passing values.

Answer 3

if (preg_match('/[^- ]+/msiu', $value)) {
    echo 'go away';
} else {
    echo 'wellcome';