如何动态填充 select option:select

Question

我遇到下拉列表中出现双值的问题，这与我想要的相反。
我有一个带有下拉列表的购物车，用户可以从中 select cakesize 以价格作为其价值。
我的设置是将购物车存储在浏览器的会话中，以便存储他 selected 的值。
我的问题是，当我加载页面时，selected cakesize 出现两次，在 选项 selected 和列表中。

<select name="cakesize" class="custom-select cakesize">
    <option selected value="<%=cake.currentPrice%>"><%=cake.currentCakeSize %></option>
    <option value="<%=cake.item.price['1000'] %>">1kg</option>
    <option value="<%=cake.item.price['1500'] %>">1.5kg</option>
    <option value="<%=cake.item.price['2000'] %>">2kg</option>
    <option value="<%=cake.item.price['2500'] %>">2.5kg</option>
    <option value="<%=cake.item.price['3000'] %>">3kg</option>
    <option value="<%=cake.item.price['3500'] %>">3.5kg</option>
    <option value="<%=cake.item.price['4000'] %>">4kg</option>
    <option value="<%=cake.item.price['4500'] %>">4.5kg</option>
    <option value="<%=cake.item.price['5000'] %>">5kg</option>
 </select>

保持这样可以吗？

Answer 1

正确的做法如下

<select name="cakesize" class="custom-select cakesize">

    <option value="<%=cake.item.price['1000'] %>" <%=cake.currentPrice == cake.item.price['1000'] ? 'selected' : '' %> >1kg</option>
    <option value="<%=cake.item.price['1500'] %>" <%=cake.currentPrice == cake.item.price['1500'] ? 'selected' : '' %> >1.5kg</option>
    <option value="<%=cake.item.price['2000'] %>" <%=cake.currentPrice == cake.item.price['2000'] ? 'selected' : '' %> >2kg</option>
    <option value="<%=cake.item.price['2500'] %>" <%=cake.currentPrice == cake.item.price['2500'] ? 'selected' : '' %> >2.5kg</option>
    <option value="<%=cake.item.price['3000'] %>" <%=cake.currentPrice == cake.item.price['3000'] ? 'selected' : '' %> >3kg</option>
    <option value="<%=cake.item.price['3500'] %>" <%=cake.currentPrice == cake.item.price['3500'] ? 'selected' : '' %> >3.5kg</option>
    <option value="<%=cake.item.price['4000'] %>" <%=cake.currentPrice == cake.item.price['4000'] ? 'selected' : '' %> >4kg</option>
    <option value="<%=cake.item.price['4500'] %>" <%=cake.currentPrice == cake.item.price['4500'] ? 'selected' : '' %> >4.5kg</option>
    <option value="<%=cake.item.price['5000'] %>" <%=cake.currentPrice == cake.item.price['5000'] ? 'selected' : '' %> >5kg</option>

</select>

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