ASP form - make option field hidden default value

I have this ASP page with a form. One field has a ul option list that assigns a value onclick, I need help to make this field hidden and assign a default value for refBerkeley.

<form NAME="InfoReqForm" ACTION="index.asp" METHOD="POST">
<input type="hidden" id="refBerkeley" name="refBerkeley" <% if fieldError(8)        then %> style="color: red; text-align: center; width="100%;" <% else %> style="color: black; text-align: center; width="100%;" <% end if %> value="<%=refBerkeleyOut %>" required/>
<div id="menu" style="text-align: center; left: 50%; font: Verdana, Arial, Helvetica, sans-serif">
<ul class="menu">
<li><a href="#" id="mainmenu" onClick="javascript:showlayer('nav')" style="text-decoration: none; color: #fff; font-size: 1.1em;">--- Select One ---    </a></li>
<ul id="nav" class="nav" style="display:none">
<li><a href="#">Television</a>
<ul>
<li><a href="#"  onClick="document.getElementById('refBerkeley').value='TVW';javascript:showlayer ('nav'); document.getElementById('mainmenu').innerHTML='Network (Ex: ABC, CBS,  NBC, Fox)'">Network (Ex: ABC, CBS, NBC, Fox)</a></li>
<li><a href="#" onClick="document.getElementById('refBerkeley').value='TVY';javascript:showlayer('nav'); document.getElementById('mainmenu').innerHTML='Cable (Ex: A&E, ESPN, TLC, etc)'">Cable (Ex: A&amp;E, ESPN, TLC, etc)</a></li>
</ul>
</li>
</ul>
</ul>
<input name="submit" type="SUBMIT" value="Submit">
</form>

The default value I want is TVW.