How can I change the name of an element in DOM?

Question

In PHP with DOM, I have a DomElement object which represents an element.

I have one case where I need to change this so its element name is

Answer 1

NOTE: I tried Calvin's code and it sort of worked for me but not quite. If the tag I was replacing had nested tags, some child tags would sometimes get lost.

The reason is that childNodes is a live DOMNodeList of a node's children, and appendChild moves the nodes around in the DOM, thus affecting the list ordering. If you just do foreach on a childNodes the loop can skip some children.

My solution was to use a while loop. This way you don't have to copy any nodes to an array.

I have packaged everything in a convenient function that takes a string and returns a string and should work with utf-8. The following is tested in PHP 5.5.9.

function renameTags($html, $oldname, $name) {
    $dom = new DOMDocument( '1.0', 'utf-8' );
    $fragment = $dom->createDocumentFragment();
    if ( $fragment->appendXML( $html ) ) {
        $dom->appendChild( $fragment );

        $nodesToAlter = $dom->getElementsByTagName( $oldname );

        while ($nodesToAlter->length) {
            $node = $nodesToAlter->item(0);

            $newnode = $node->ownerDocument->createElement($name);

            while ($node->hasChildNodes()) {
                $child = $node->childNodes->item(0);
                $child = $node->ownerDocument->importNode($child, true);
                $newnode->appendChild($child);
            }
            foreach ($node->attributes as $attr) {
                $attrName = $attr->nodeName;
                $attrValue = $attr->nodeValue;
                $newnode->setAttribute($attrName, $attrValue);
            }
            $newnode->ownerDocument->replaceChild($newnode, $node);

        }
        return $dom->saveHTML();
    } else {
        //error
    }
}


$html = 'Testing nested tags in  html strings and stuff';

echo renameTags($html, 'b', 'strong');

Prints:

Testing nested tags in  html strings and stuff