title: Angular 2: Regex to accept only positve integers and no dots
body: <p>I got a input field with the type number. Now I'm trying to add a pattern to it that only allows positive integers and no dots or commas! But I cant find a good regex for it</p>
  
  <p>so</p>
  
  <p><strong>allowed</strong></p>
  
  <ul>
  <li>0</li>
  <li>01</li>
  <li>100</li>
  </ul>
  
  <p><strong>not allowed!</strong></p>
  
  <ul>
  <li>-1</li>
  <li>1-</li>
  <li>1+</li>
  <li>1.0</li>
  <li>1.1</li>
  <li>1+</li>
  <li>+1</li>
  <li>1,2</li>
  </ul>