/**
  * Check if element is a button
  * 
  * @param Element $element
  * @return boolean
  */
 protected static function isButton($element)
 {
     if (!$element instanceof Element) {
         return false;
     }
     return $element instanceof Button || $element instanceof Input && in_array($element->attr['type'], ['button', 'submit', 'reset']) || $element->hasClass('btn') || $element->getOption('btn');
 }