private function getSubmitStateNodeList()
{
$xpath = new DOMXPath($this->document);
$nodeList = $xpath->query('//input[@type="submit"] | //button[@type="submit"]');
/** @var DOMElement $node */
foreach ($nodeList as $node) {
$name = $node->getAttribute('name');
if (!$name) {
// At least a name is needed to submit a value.
continue;
}
(yield $name);
}
}