title: Regular Expression advice for [Alphanumeric][alphanumeric.-_@] 31 characters
body: <p>I'm looking to do a name check using regex in javascript. </p>
  
  <ol>
  <li>The value can contain alphanumeric and following special characters
  ('-', '.' '_' and '@').</li>
  <li>It should always start with an alphanumeric character.</li>
  <li>It should not be an empty string.</li>
  <li>Maximum allowed length for this parameter is 31 characters.</li>
  <li>This parameter is case-insensitive.</li>
  </ol>
  
  <p>I came up with this, but feel it's incorrect. Any advice on how to have it foolproof?</p>
  
  <pre><code>^[A-Za-z0-9]+[A-Za-z0-9_@-.]{30}
  </code></pre>