title: Max length UITextField
body: <p>When I've tried <a href="https://stackoverflow.com/questions/24641982/how-to-you-set-the-maximum-number-of-characters-that-can-be-entered-into-a-uitex">How to you set the maximum number of characters that can be entered into a UITextField using swift?</a>, I saw that if I use all 10 characters, I can't erase the character too.</p>
  
  <p>The only thing I can do is to cancel the operation (delete all the characters together).</p>
  
  <p>Does anyone know how to not block the keyboard (so that I can't add other letters/symbols/numbers, but I can use the backspace)?</p>