Javascript 如果元素不存在，如何用JS删除类？

在我的网站上，导航栏右侧有一个菜单。当搜索在当前页面上可用时，它将显示搜索

我想在搜索可用时显示一个图标

所有搜索块都具有类

。视图公开形式

，并显示在

#导航栏折叠秒

我在我的图标中添加了用于隐藏图标的类

。icon navbar alert disable

当

.views公开表单

类出现在

#导航栏折叠秒

中时，如何删除

.icon导航栏警报禁用

类

以下是隐藏图标的css代码：

.region-navigation-menu-second .navbar-toggle-second .icon-navbar-alert-disable {
    display: none;
}

<div{{ attributes }}>

<a class="navbar-toggle-second collapsed" data-toggle="collapse" data-target="#navbar-collapse-second" aria-expanded="false">

  <div class="icon-navbar">
    <span class="fa-layers fa-3x">
      <i class="far fa-circle"></i>
      <span class="navbar-icon-open">
        <i class="fas fa-filter" data-fa-transform="shrink-9"></i>
      </span>
      <span class="navbar-icon-close">
        <i class="fas fa-times" data-fa-transform="shrink-8"></i>
      </span>
    </span>
  </div>

  <div class="icon-navbar-alert icon-navbar-alert-disable">
    <span class="fa-stack fa-lg">
      <i class="fas fa-circle fa-stack-2x"></i>
      <i class="fas fa-filter fa-stack-1x fa-inverse"></i>
    </span>
  </div>

</a>

</div>

以下是带有图标的my manu按钮的代码：

.region-navigation-menu-second .navbar-toggle-second .icon-navbar-alert-disable {
    display: none;
}

<div{{ attributes }}>

<a class="navbar-toggle-second collapsed" data-toggle="collapse" data-target="#navbar-collapse-second" aria-expanded="false">

  <div class="icon-navbar">
    <span class="fa-layers fa-3x">
      <i class="far fa-circle"></i>
      <span class="navbar-icon-open">
        <i class="fas fa-filter" data-fa-transform="shrink-9"></i>
      </span>
      <span class="navbar-icon-close">
        <i class="fas fa-times" data-fa-transform="shrink-8"></i>
      </span>
    </span>
  </div>

  <div class="icon-navbar-alert icon-navbar-alert-disable">
    <span class="fa-stack fa-lg">
      <i class="fas fa-circle fa-stack-2x"></i>
      <i class="fas fa-filter fa-stack-1x fa-inverse"></i>
    </span>
  </div>

</a>

</div>

更新

(function ($) {

  if ($('#navbar-collapse-second').hasClass('views-exposed-form')) {
       $('#block-togglenavigationsecond').removeClass('icon-navbar-alert-disable');
  } else { 
       $('#block-togglenavigationsecond').addClass('icon-navbar-alert-disable');
  };

})(window.jQuery);

---

您正在jQuery中寻找hasClass选择器吗

如果是这样的话，用If语句包装它，在里面你可以显示你想要的结果

if ($('#navbar-collapse-second').hasClass('views-exposed-form') === false) {
    $('#block-togglenavigationsecond').removeClass('icon-navbar-alert-disable');
} else { 
    $('#block-togglenavigationsecond').addClass('icon-navbar-alert-disable');
};