[jQuery] Extracting content from a div?

Hi,

I need to try and extract the following from a STRING (not the current
page);

                        <div class="error">
                                <ul>
                                        <li>Gast Email der Rezension kann nicht 
den Wert 'undefined'
                                        speichern.</li>
                                </ul>
                        </div>

How would I do this?  I had a look on google, but all they seem to be
talking about is extracting from the current page, which I don't want :
(

TIA!

Andy