Document::createElement

public function createElement($tagName)
{
	static $classByTag = array();

	$tagName = mb_strtoupper($tagName);
	$elementClass = "Bitrix\Main\Web\DOM\Element\" . $tagName;

	if(!isset($classByTag[$tagName]))
	{
		if(class_exists($elementClass))
		{
			$classByTag[$tagName] = $elementClass;
		}
		else
		{
			$classByTag[$tagName] = false;
		}
	}

	if($classByTag[$tagName])
	{
		$elementClass = $classByTag[$tagName];
		$node = new $elementClass($tagName);
	}
	else
	{
		$node = new Element($tagName);
	}

	$node->setOwnerDocument($this);
	return $node;
}