PHP XMLREADER Nested Elements

Hi I am trying to use XML Reader to read some dynamic xml where I don't know the element names. I need to use XML Reader and not SimpleXML as that is all that is available on my server. The trouble I am having is trying to have something that can deal with both nested and un-nested elements. My XML looks like

<1stelement>
      <2ndelement>Text</2ndelement>
    <3rdelement>
      <4thelement>Text</4thelement>
  </3rdelement>
</1stelement>

But Could also look like:

<1stelement>Something</1stelement>

I am using the following code:

    while ($reader->read()) {
        if ($reader->nodeType == XMLReader::ELEMENT) {
            $element = $reader->name;
            //$elementarray[] = $element;
            echo $element;
            if ($reader->depth <1){echo"</br>";}
        }

        if ($reader->nodeType == XMLReader::TEXT) {
            $value = $reader->value;
            $valuearray[] = $value;
            echo " : ".$value."</br>";                 
        }
    }

This outputs

1stElement2ndelement : text

I cannot find anyway in the poorly documented XML Reader to have the output

1stElement:
2ndelement: text

which I can populate an array with.

Any help is appreciated as I am new to PHP.