Take the value of a listed <td> (JSP)

Question

Eae guys.

I’m making a system for the college, I wonder if you forum could solve a problem that I’m going through.

My sell screen needs to take the unit price value that is on a chart. The user can put the service he wants that is in a box, by clicking on the service need to automatically pull the unit price. What lists my box is a c:foreach.

<section id="principal">
    <form name="formVendas" method="get" action= "" method="get">
        <h1>Vender</h1>
        <p><label>Nome do serviço:<select id="camposervico" class="tempNome" name="servico">
                    <c:forEach var="servico" items="${dao.listar()}">
                        <option name="${servico.nomeServico}">${servico.nomeServico}</option>
                    </c:forEach>
                </select></label>
            <label>Quantidade:<input type="text" class="tempQuantidade" name="quantidade"></label>
            <label>Preço Unitário:<input type="text" class="tempPrecoUnitario" name="precounitario" ></label>
            <label>Valor total:<input type="text" class="tempInsert"  value="" name="valortotal"></label>
            <button type="button" id="tempBtn" onclick="calcularTotal()">Adicionar</button>
        </p>

        <table width="100%">
            <thead>
                <tr>
                    <th>Serviço</th>
                    <th>Preço Unitário</th>
                    <th>Quantidade</th>
                    <th>Valor Total</th>
                    <th>Remover</th>
                </tr>
            </thead>
            <tbody></tbody>
        </table>



    </form>
</section>
<script src="./resources/bootstrap/js/bootstrap.min.js"></script>