title: Javascript regex for integer only, not to start with 0 but allow 0
body: <p>I need a regex to validate integer numbers. <code>05 and 00</code> are not allowed but <code>0</code> is allowed.
  Currently I have this:</p>
  
  <pre><code>/^[1-9]\d*$/
  </code></pre>
  
  <p>But it does not allow <code>0</code>. Thanks for help.</p>