title: Regex for number up to 16 digits with optional decimal any place within number
body: <p>I'm trying to find the correct regex pattern to match any number up to 16 digits max, with an optional decimal point anywhere in the number.  Here are some examples.</p>
  
  <p>Valid:</p>
  
  <ul>
  <li>9999999999999999</li>
  <li>0.000000000000001</li>
  <li>3.24</li>
  <li>1.2</li>
  <li>0.00003</li>
  </ul>
  
  <p>Invalid:</p>
  
  <ul>
  <li>12345678910111213</li>
  <li>59.492.5</li>
  </ul>