How refer to UL tags in my Javascript function?

[ReportingAnalyst]

I have this HTML code which is built dynamically:

<[b]ul id="UI2271284"[/b] style="display: none">
							
<li>
	<input type="radio" name="empid" id="empid40962" value="40962">Julie Breslow&nbsp;<font size=1>(40962)</font>
</li>

<li>
	<input type="radio" name="empid" id="empid41382" value="41382">Frank Duplak&nbsp;<font size=1>(41382)</font>			
</li>

</ul>

My javascript function refers to this UL tag. But how I refer to the 'UI' before the number?

Javascript function is:

function s_Hide(el){
[b]	obj = document.getElementById(el).style;[/b]
	(obj.display == 'none')? obj.display = 'block' : obj.display = 'none';
	//Need to store the current state on a cookie
	var uniqueStr = '&' + el + '&'
	if (obj.display == 'block')
	{
	  // add it to the string openedItems
	  //alert("Add '" + uniqueStr + "'");
	  openedItems = openedItems.concat(uniqueStr);
	}
	else
	{
	  // remove it from the string openedItems
	  //alert("Remove '" + uniqueStr + "'");
	  openedItems = openedItems.replace(uniqueStr, '');
	}
	//alert(openedItems);
}

 

[ReportingAnalyst]

I added this line to the Javascript function to refer to the UL tag id:

elID = 'UI_'+ el;
obj = document.getElementById(elID).style;