(PHP 4 >= 4.1.0)
DomElement::tagname — Returns the name of the current element
Returns the name of the current node. Calling this function is the same as accessing the tagname property, or calling DomNode::node_name on the current node.
Returns the name of the current DomElement node.
Example #1 Getting the node name
<?php
include("example.inc");
if (!$dom = domxml_open_mem($xmlstr)) {
    echo "Error while parsing the document\n";
    exit;
}
$root = $dom->document_element();
echo $root->tagname();   // chapter
echo $root->tagname;     // chapter
echo $root->node_name(); // chapter
?>
Use the tagName property of the DOMElement object.