<div class="collapse">
            <div class="collapseItem">
                <div class="title">标题1</div>
                <div class="content">内容1</div>
            </div>
            <div class="collapseItem">
                <div class="title">标题2</div>
                <div class="content">内容2</div>
            </div>
            <div class="collapseItem">
                <div class="title">标题3</div>
                <div class="content">内容3</div>
            </div>
  </div>

let collapse=new Collapse(".collapse",{"single":false})