Access querystring and give it value

Access querystring and give it value

How do i acces variable: id inside <a href..  and append my querystring variable to it?

example
<div id="email">
<a href="Emaillist_3212.html?id="><img alt="list" src="pics/email32.png"/>
<span class="name">Emails (?)</span>
<span class="arrow"></span>
</a>
</div>

I want: id=contact_id; (i already have contact_id on document.ready)
$('#email > a ...???......).append(contact_id);