javascript - 计算 jQuery 中选定选项的数量？

Question

我有多个具有相似名称的下拉菜单，我想计算选择了选项的下拉菜单的数量。

例如，

<select class="custom_select" name="customSelect1" id="customSelect1">
    <option value="0">0</option>
    <option value="1">1</option>
    <option value="2">2</option>
</select>

<select class="custom_select" name="customSelect2" id="customSelect2">
    <option value="0">0</option>
    <option value="1">1</option>
    <option value="2">2</option>
</select>

<select class="custom_select" name="customSelect3" id="customSelect3">
    <option value="0">0</option>
    <option value="1">1</option>
    <option value="2">2</option>
</select>

这里我只想计算那些选择了值 1 或 2 的下拉菜单的数量。

Answer 1

您可以通过 $(".custom_select>option:not([value='0']):selected").length 简单地检查除 value = 0 之外的选项的长度

console.log($(".custom_select>option:not([value='0']):selected").length)
$(".custom_select").off("change").on("change", function(){
	console.log($(".custom_select>option:not([value='0']):selected").length)
});

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<select class="custom_select" name="customSelect1" id="customSelect1">
    <option value="0">0</option>
    <option value="1">1</option>
    <option value="2">2</option>
</select>

<select class="custom_select" name="customSelect2" id="customSelect2">
    <option value="0">0</option>
    <option value="1">1</option>
    <option value="2">2</option>
</select>

<select class="custom_select" name="customSelect3" id="customSelect3">
    <option value="0">0</option>
    <option value="1">1</option>
    <option value="2">2</option>
</select>