CodingForums.com - Resolved Prototype tabs script "crashing" when attempting to reassign active "class"

I'm using a tab script I ran across that works only if I remove the portion of the function that removes the "active" class on the active tab when a new tab is selected.

The script requires prototype.

Code:

var visibleTabContent = 'one';

function switchTabs(ulId, clickedListItem, clickedListItemsDivId) {

  if (!$(clickedListItemsDivId).visible()) {

    $(visibleTabContent).hide();                                             //hide the DIV contents for the old tab

    $(ulId).select('li.active').invoke('removeClassName', 'active'); //remove the "active_tab" class from the old tab

    $(clickedListItem.id).addClassName('active');                        //add the "active" class to the new tab

    $(clickedListItemsDivId).show();                                         //show the DIV contents for the new tab

    visibleTabContent = clickedListItemsDivId;                               //save the name of the active tab for future reference

  }

}

IF I remove

Code:

$(ulId).select('li.active').invoke('removeClassName', 'active');

The tab selection functions; however, as one might guess, it's not shifting the "active" style from tab to tab, it's simply assigning it.

I've tried doing

Code:

$(ulId).select('li.active').removeClassName('active');

sinse "removeClassName" is a prototype function, but it delivers the same results.

Error: $(ulId).select is not a function ???

The accompanying mark-up is

Code:

<ul id="tabs_menu" class="margin_20 clearfix">



        <li  id="cat1" class="active" onclick="switchTabs('tabs_menu', this, 'one')">Cat 1 +</li>

        <li  id="cat2" onclick="switchTabs('tabs_menu', this, 'two')">Cat 2 +</li>

        <li  id="cat3" onclick="switchTabs('tabs_menu', this, 'three')">Cat 3 +</li>

</ul>

<div id="one">

        <!--Content Here-->

</div>

<div id="two">

        <!--Content Here-->

</div>

<div id="three">

        <!--Content Here-->

</div>

Any advice?

Thanks