Search box options drop down - Switch active to selected?

[MrTIMarshall]

Hello,

I have a search box on my website, with a drop down to show the options to fine tune your search. Inside this drop down, there is a list, however I do not know how many options will be in this list.

            <div class="NewSearchActions">
                <a href="#" onclick="mopen('searchby'); parentNode.className=('active')"><b class="caret"></b></a>
                <div id="searchby">
                    <div class="wrap">
                        <ul>
                        	<li><a href="#">Item One</a></li>
                            <li><a href="#">Item Two</a></li>
                            <li><a href="#">Item Three</a></li>
                            <li><a href="#">Item Four</a></li>
                    	</ul>
                    </div>
                </div>
            </div>

You can view the page for the website here; https://tornhq.com/Top_Menu/Index-New.html, which looks a bit messy for this drop down as I need to style it properly. I would like the one you click on to set to the active class and, if another one has previously been clicked to switch back.

Thank you for any help and/or advice!

Best Regards,
Tim