Dropdown (return current value)

[mmchu]

Hi, i need some help with this if is possible.

I make this dropdown:

<dl class="dropdown">
<dt><a><span>Select a Field</span></a></dt>
<dd>
<ul id="menu-tags-menu" class="menu">
<li id="menu-item-159" class="menu-item current-menu-item"><a href="http://myweb.com.ar/portfolio/">All Fields</a></li>
<li id="menu-item-54" class="menu-item"><a href="http://myweb.com.ar/tag/branding/">Branding</a></li>
<li id="menu-item-55" class="menu-item"><a href="http://myweb.com.ar/tag/print-design/">Print Design</a></li>
<li id="menu-item-57" class="menu-item"><a href="http://myweb.com.ar/tag/web-design/">Web Design</a></li>
<li id="menu-item-56" class="menu-item"><a href="http://myweb.com.ar/tag/ui-design/">UI Design</a></li>
<li id="menu-item-52" class="menu-item"><a href="http://myweb.com.ar/tag/motion-graphics/">Motion Graphics</a></li>
<li id="menu-item-53" class="menu-item"><a href="http://myweb.com.ar/tag/illustration/">Illustration</a></li>
</ul>
</dd>
</dl>

Working with jquery and this code:

$(document).ready(function() {
	$(".dropdown dt a").click(function() {
		$(".dropdown dd ul").toggle();
	});
	$(".dropdown dd ul li a").click(function() {
		var text = $(this).html();
		$(".dropdown dt a span").html(text);
		$(".dropdown dd ul").hide();
		$("#result").html("Selected value is: " + getSelectedValue("sample"));
	});
	function getSelectedValue(id) {
		return $("#" + id).find("dt a span.value").html();
	}
	$(document).bind('click', function(e) {
		var $clicked = $(e.target);
		if (! $clicked.parents().hasClass("dropdown"))
		$(".dropdown dd ul").hide();
	});
});

This works very well.. but i need the dt a span show me the value of the current li (<li class="current-menu-item">), so instead "Select a Field" must say "All Fields" (current value in this example), and when i go to "Motion Graphics" (for example), when page is load must say "Motion Graphics".

Can i do this adding a variable to take the value of current li and droping when document.ready?

Thanks

[mmchu]

Here you can see how it works:
http://www.patricioherrera.com.ar/portfolio

Any ideas?