simple prototype form validation

Event.observe('submit_button','click', function(e) {
  e.stop();
  
  var contact = $('form_name').getValue();
  var comment = $('form_comment').getValue();
  if(contact != '') {
    var phoneRegExp = new RegExp('^[+]{0,1}[0-9]+$');
    var emailRegExp = new RegExp('^[a-zA-Z0-9._+-]+[@]{1}[a-zA-Z0-9._-]+[.]{1}[a-zA-Z0-9]+$');
    
    if(phoneRegExp.test(contact) || emailRegExp.test(contact)) {
      $('contact_form').submit();
    }
  }
});