how to get values of description list, with terms and descriptions in DOMXPath?

So far i get complete html of page now i want to get data of description list from that page. i am new with web scrapping so please help me out with this?

Here is html that i want to get.

<dl id="specs">

    <dt class="section">Keyboard</dt>
    <dt>Keyboard</dt>
    <dd>88 keys</dd>
    <dt>Touch Sensitivity</dt>
    <dd>Key Touch: 5 types, fixed touch</dd>
    <dt>Keyboard Mode</dt>

    <dt class="section">Sound Generator</dt>
    <dt>Piano Sound</dt>
    <dd>SuperNATURAL Piano Sound</dd>

</dl>