title: Drupal form validation functions
body: <p>Is there anyway say Drupal to validate form elements like email fields, passwords, numeric fields validate automatically lets say bind a system validator</p>
  
  <p><code><pre>
  $form['email] = array(
     '#title' => t('Email'),
     '#type' => 'textfield',
     <strong>'#validate_as' => array('email', ...),</strong>
     ...
  );
  </pre>
  </code></p>