title: Disable some characters from input field
body: <p>I have found some instructions similar, but none helps, all of them are either for special chars or for digits.</p>
  
  <p>I need to make user type only 1 , 2 , 3, 4, 5, N, O, A, B, C . all other characters should be restricted.</p>
  
  <p>Any way I can make my own selection of restricted/allowed chars for inputs ?</p>
  
  <ul>
  <li>Not very familiar with javascript.</li>
  </ul>