title: HTML5 input pattern - exactly 'N' quantity of numbers
body: <p>I want an input that it can only enter exactly N quantity of numbers , no less, no more.</p>
  
  <p>I have tried this:
  Example with 4 digits.</p>
  
  <pre><code>&lt;input type="text" name="myinput" pattern="[0-9]{4}" title="Only four (4) digits."&gt;
  </code></pre>
  
  <p>But it does not work, someone knows how to fix it?</p>