javascript - 如何在javascript中查找列表中的选定元素

Question

我有一个正在处理的 jsp，我需要找出列表中的哪个项目被选中。

这是 jsp 的屏幕截图:

代码如下:

<% Venue v = (Venue)session.getAttribute("currentVenue"); %>
<% List<Conceptual_Package> cpList = Conceptual_PackageDAO.getInstance().getByVenue(v.getId()); %>

What Packages do you want to see?

 <form method="post" action="ttp.actions.Sale3PackAction.action">
 <select name="packid" id="packid">
     <% for (Conceptual_Package cp: cpList) { %>
    <option value="<%=cp.getId()%>"><%=cp.getName1()%></option>
    <% } %>


 </select>

    <input type="button" value="  next  " onclick="getSeats();"/>

    </form>


<!--new-->


Available Seats:

 <select name="aSeats" size="10" id="aSeats">

 </select>


    <input type="button" value="  add  " onclick="addToCart();"/>


Selected Seats:
 <form method="post" action="ttp.actions.sale4Action.action">
     <select name="Seat2" size="10" id="seat2">

     </select>



    </form>



<jsp:include page="/footer.jsp"/>

Answer 1

可以得到选中的<option>通过与 <select> 交谈的 DOM 对象对象:

var select = document.getElementById('packId');
var selectedOption = select.options[select.selectedIndex];
alert("Selected option: " + selectedOption.value);