I am having problems extending a class correctly, or maby it is not possible? Norsk går forsåvidt fint, er bare vant til engelsk Example: <?php class extDOMDocument extends DOMDocument { public function innerHTML($element){ $innerHTML = ""; $children = $element->childNodes; foreach ($children as $child) { $innerHTML .= $element->ownerDocument->saveHTML($child); } return $innerHTML; } } $dom = new extDOMDocument('1.0'); $dom->loadHTML('<div id="first">First div</div><div id="second">Second div</div><div id="Third">Third div</div>'); // This works echo $dom->innerHTML($dom->getElementById('second')); // This would be better - but doesnt work. echo $dom->getElementById('second')->innerHTML(); UPDATE: More thoughts around my OOP question I understand the reason now, however do not know how to solve it. getElementById() creates a new DOMElement which is not extended from extDOMDocument or DOMDocument it seems - which I assumed. That explains the reason for the method not being found in my wanted functionality. From what I read of this I could rewrite the function DOMDocument::getElementById() to use an extended version of DOMElement. Then again - I do not know what the code for the function DOMDocument::getElementById() is... a) Is there a way to find the code for DOMDocument::getElementById so I could override it from my extDOMDocument b) Can I extend a class - then override the original class with the extended one? This way I could extend the DOMElement with my innerHTML() function. Interesting links that could have sollution, I tried however didnt succeed http://stackoverflow.com/questions/2658906/is-there-any-way-to-redeclare-a-class-safely-in-php
