title: how to add a character into a textbox
body: <p>i would like to add a character to a text-box that separates two characters from two like this :</p>
  
  <pre><code>22:11
  </code></pre>
  
  <p>so when the user enters 22 it auto switch to after the separator and then the user can enter 11.</p>
  
  <p>how can i do this , thanks.</p>