title: RexEx for first half of Email match
body: <p>I am trying to create a regular expression to match to the first half of an email address.
  Legitimate values for the domain are:</p>
  
  <ul>
  <li>First.Name</li>
  <li>First.Middle.Name</li>
  <li>First.I.Name</li>
  <li>First.I.N.Name (here there is no limit to the number of initials but the most I have seen are 2)
  Also in some cases an _ has been used I think to substitute an apostrophe as in O_Neil</li>
  </ul>
  
  <p>The expression I have at the moment is [a-zA-Z_]+(.[a-zA-Z_])* but this is not working... Any help appreciated.</p>