title: Regular expression to detect string contains only . or ? or?
body: <p>I would like to match string which contains only . or only ? or only !. The string can contains many chars e.g "..." or "????".</p>
  
  <p>I can create expression for one mark ^(!+)$ but how to add or condition? Something like this: ^(!+)$|^(?+)$|^(.\+)$ doesn't work.</p>