js get input value implementation code of input tag

<%
Date d = new Date();
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
%><%
UserInfo userInfo = (UserInfo) (ToftConst.Toft_SessionKey_UserData);
%>

<t:searchform >
<ul class="c3 l120 clearfix">
<li>
<label>Date of generation:</label>
<t:date name="generate_date" value="<%=(d)%>"/>
</li>
<li>
<label>Maintenancer:</label>
<input type="text" name="maintenance_men" maxlength="50" value="${ }"/>
</li>
</ul>
</t:searchform> <script type="text/javascript">
function InsertData(){
var generate_date=("generate_date").value;
var maintenance_men=("maintenance_men").value;
alert(maintenance_men);

</script>