Nette\Forms\Form::isMethod PHP Method

    public function isMethod($method)
    {
        return strcasecmp($this->getElementPrototype()->method, $method) === 0;
    }

 /**
  * Renders form end.
  * @return string
  */
 public static function renderFormEnd(Form $form, $withTags = TRUE)
 {
     $s = '';
     if ($form->isMethod('get')) {
         foreach (preg_split('#[;&]#', parse_url($form->getElementPrototype()->action, PHP_URL_QUERY), NULL, PREG_SPLIT_NO_EMPTY) as $param) {
             $parts = explode('=', $param, 2);
             $name = urldecode($parts[0]);
             if (!isset($form[$name])) {
                 $s .= Html::el('input', ['type' => 'hidden', 'name' => $name, 'value' => urldecode($parts[1])]);
             }
         }
     }
     foreach ($form->getControls() as $control) {
         if ($control->getOption('type') === 'hidden' && !$control->getOption('rendered')) {
             $s .= $control->getControl();
         }
     }
     if (iterator_count($form->getComponents(TRUE, Nette\Forms\Controls\TextInput::class)) < 2) {
         $s .= "<!--[if IE]><input type=IEbug disabled style=\"display:none\"><![endif]-->\n";
     }
     return $s . ($withTags ? $form->getElementPrototype()->endTag() . "\n" : '');
 }