I would like to change the value of a single hidden input onclick. The possible values are text, email and URL. I've tried all kinds of "ways" (inline and in function in a variety of ways,) but nothing. I stripped it down one last time to give it another go, but realize I'm out of ideas, so the code below is simply where I've thrown in the towel.

Can someone make this work with a JS function, so that each link may be clicked and change the hidden input's value to the respective value?

Code:
<form id="dataForm" name="dataForm" method="post" action="index.php" enctype="application/x-www-form-urlencoded">
    <div>
        <input type="hidden" name="dataType" id="dataType" value="" />
        <ul class="tab-headers">
            <li id="tab-header1" onclick="">Text</li>
            <li id="tab-header2" onclick="" class="active">Email</li>
            <li id="tab-header3" onclick="">URL</li>
        </ul>
......
Thanks for your wisdom!