我有这样的标记

<div class="personal-menu-content">
    <ul>
         <li><a data-menu-item="lessons" class="personal-menu-item lessons" href="#">Lessons</a></li>
         <li><a data-menu-item="profile" class="personal-menu-item profile" href="#">Edit Profile</a></li>
         <li><a data-menu-item="library" class="personal-menu-item library" href="#">Your Library</a></li>
    </ul>
</div>

<div class="contents">
    <div id="lessons">
        <h2>Lessons text here</h2>
        <p>Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s</p>
    </div>
    <div id="profile">
        <h2>profile text here</h2>
        <p>It is a long established fact that a reader will be distracted by the readable content of a page when looking at its layout. The point of using Lorem Ipsum is that it has a more-or-less normal distribution of letters, as opposed to using 'Content here, content here', making it look like readable English.</p>
    </div>
    <div id="library">
        <h2>library text here</h2>
        <p>Contrary to popular belief, Lorem Ipsum is not simply random text. It has roots in a piece of classical Latin literature from 45 BC, making it over 2000 years old. Richard McClintock, a Latin professor at Hampden-Sydney College in Virginia, looked up one of the more obscure Latin words,</p>
    </div>
</div>

和像这样的JS

$('div#profile').show();
    $('body').on('click','a.personal-menu-item', function(e) {
        e.preventDefault();
        var selectedItem = $(this).attr('data-menu-item');
        if(selectedItem == 'lessons') {
            $('div#lessons').show();
            $('div#profile').hide();
            $('div#library').hide();
        }
        if(selectedItem == 'profile') {
            $('div#lessons').hide();
            $('div#profile').show();
            $('div#library').hide();
        }
        if(selectedItem == 'library') {
            $('div#lessons').hide();
            $('div#profile').hide();
            $('div#library').show();
        }
    });

所以在这里，我希望当我点击课程时，只有课程内容会显示出来，就像这样，当我点击配置文件和库时，只有配置文件和库会显示出来。在这里，它的工作很好，但我想知道如何添加一个类活动时，一个项目被点击在锚标记。假设我点击了lessons，那么一个活动类应该被添加到lessons锚标记中，当我点击了profile，那么活动类应该被从lessons锚标记中移除，它应该在profile锚标记中添加活动类。这是我的小提琴