/**
  * (non-PHPdoc)
  * @see xhtml/XhtmlElement#GetOpenTagXhtml()
  */
 public function GetOpenTagXhtml()
 {
     # For a file upload control, use the maxlength attribute to set a max file size
     $max_size = '';
     if ($this->i_mode == TextBoxMode::File()) {
         $max_size = new TextBox('MAX_FILE_SIZE', $this->GetMaxLength());
         $max_size->SetMode(TextBoxMode::Hidden());
         $this->RemoveAttribute('maxlength');
         // not valid option
     }
     return $max_size . parent::GetOpenTagXhtml();
 }