Accesses a valid index and an invalid index.
<?php
$dom = Dom\HTMLDocument::createFromString('<p class="font-bold important"></p>', LIBXML_NOERROR);
$p = $dom->body->firstChild;
$classList = $p->classList;
var_dump(
$classList->item(0),
$classList->item(100),
);
?>
The above example will output:
string(9) "font-bold"
NULL