如何获取Bootstrap手风琴的index / id面板

如何解决如何获取Bootstrap手风琴的index / id面板

我正在尝试获取手风琴活动面板的索引。

我的示例：

我想将2号保存在变量“ index”中，因为此刻手风琴的第二个面板处于活动状态。

accordion.html：

<div id="accordion">
             <form id="creaAppunt" th:action="@{/provaCreaAppuntamento}" method="post" th:object="${appuntamento}">
                  <div class="card">
                    <div class="card-header" data-toggle="collapse" data-target="#collapSEOne" aria-expanded="true" aria-controls="collapSEOne"  id="headingOne" index="1">
                          <h5 class="mb-0">
                            <div class="text-center">
                                Selezione Prestazione
                            </div>
                          </h5>
                    </div>
                
                    <div id="collapSEOne" class="collapse show" aria-labelledby="headingOne" data-parent="#accordion">
                       
                          <div class="card-body">
                            <div class="form-row p-4">
                                <div class="form-group col-md-6">
                                    <label class="labelDoc">Seleziona Prestazione</label>
                                    <select id="prestazione" class="form-control" th:field="${appuntamento.idPrenotazione}">
                                        <option value="">---</option>
                                        <option th:each="prestazione: ${prestazioni}" 
                                            th:value="${prestazione.codice}" 
                                            th:utext="${prestazione.denominazione}"
                                        />
                                    </select>
                                </div>
                            </div>
                          </div>
                           <div data-toggle="collapse" data-target="#collapseTwo" aria-expanded="false" aria-controls="collapseTwo" id="btnSalvaPrestazione">Avanti</div>
                        
                    </div>
                  </div>
                  <div class="card">
                    <div class="card-header collapsed " id="headingTwo" data-toggle="collapse" data-target="#collapseTwo" aria-expanded="false" aria-controls="collapseTwo" index="2">
                      <h5 class="mb-0">
                        <div class="text-center">
                         Selezione Sede
                        </div>
                      </h5>
                    </div>
                    <div id="collapseTwo" class="collapse" aria-labelledby="headingTwo" data-parent="#accordion">
                        <div class="card-body">
                            <div class="form-row p-4">
                                <div class="form-group col-md-6">
                                    <label class="labelDoc">Sede Prenotazione</label>
                                    <select id="sede" class="form-control" th:field="*{sede}">
                                        <option value="">---</option>
                                    </select>
                                </div>
                            </div>
                        </div>
                    </div>
                  </div>
                  <div class="card">
                    <div class="card-header collapsed" id="headingThree" data-toggle="collapse" data-target="#collapseThree" aria-expanded="false" aria-controls="collapseThree" index="3">
                      <h5 class="mb-0">
                        <div class="text-center" >
                          Collapsible Group Item #3
                        </div>
                      </h5>
                    </div>
                    <div id="collapseThree" class="collapse" aria-labelledby="headingThree" data-parent="#accordion">
                      <div class="card-body">
                        Anim pariatur cliche reprehenderit,enim eiusmod high life accusamus terry richardson ad squid. 3 wolf moon officia aute,non cupidatat skateboard dolor brunch. Food truck quinoa nesciunt laborum eiusmod. Brunch 3 wolf moon tempor,sunt aliqua put a bird on it squid single-origin coffee nulla assumenda shoreditch et. Nihil anim keffiyeh helvetica,craft beer labore wes anderson cred nesciunt sapiente ea proident. Ad vegan excepteur butcher vice lomo. Leggings occaecat craft beer farm-to-table,raw denim aesthetic synth nesciunt you probably haven't heard of them accusamus labore sustainable VHS.
                      </div>
                    </div>
                  </div>
                  </form>
                </div>

accordion.js：

$(document).ready(function() {
    
    $('#prestazione').selectize({
        valueField: 'codice',labelField: 'denominazione',searchField: 'denominazione',onChange: function () {

        }
    });
    
    $('#sede').selectize({
        valueField: 'codice',searchField: 'denominazione'
    });
    
    var index = $('#accordion .in').parent().attr("id");

能帮我吗？ 我需要获取索引，因为我想要一个清除并禁用所有被索引面板的功能。

谢谢！