/**
  * FormHandler::uploadField()
  *
  * Create a uploadField on the form
  *
  * @param string $title: The title of the field
  * @param string $name: The name of the field
  * @param array $config: The configuration used for the field
  * @param string $validator: The validator which should be used to validate the value of the field
  * @param string $extra: CSS, Javascript or other which are inserted into the HTML tag
  * @param string $alertOverwrite: Do we have to alert the user when he/she is going to overwrite a file?
  * @return void
  * @access public
  * @author Teye Heimans
  */
 function uploadField($title, $name, $config = array(), $validator = null, $extra = null, $alertOverwrite = null)
 {
     require_once FH_INCLUDE_DIR . 'fields/class.UploadField.php';
     // create a new uploadfield
     $fld = new UploadField($this, $name, $config);
     if (!empty($validator)) {
         $fld->setValidator($validator);
     }
     if (!empty($extra)) {
         $fld->setExtra($extra);
     }
     if (!is_null($alertOverwrite)) {
         $fld->setAlertOverwrite($alertOverwrite);
     }
     // register the field
     $this->_registerField($name, $fld, $title);
     // set that this form is using uploadfields
     $this->_upload[] = $name;
 }