title: Allow only a single point in decimal numbers
body: <p>How can I modify this regular expression to allow numbers with just one point?</p>
  
  <pre><code>/[^0-9\.]/g
  </code></pre>
  
  <p>It currently allows:</p>
  
  <ul>
  <li>0</li>
  <li>0.13</li>
  <li>0.13.1 (this should not be allowable)</li>
  </ul>