添加/删除SIDENAV的活动类

Question

如何为 SIDENAV onclick事件添加/删除active课程？

<nav class="sidenav">
    <section class="sidenav-content">
        <a href="..." class="nav-link active">
            Nav Element 1
        </a>enter code here
        <a href="..." class="nav-link">
            Nav Element 2
        </a>
        <section class="nav-group collapsible">
            <input id="tabexample1" type="checkbox">
            <label for="tabexample1">Collapsible Nav Element</label>
            <ul class="nav-list">
                <li><a class="nav-link">Link 1</a></li>
                <li><a class="nav-link">Link 2</a></li>
            </ul>
        </section>
        <section class="nav-group">
            <input id="tabexample2" type="checkbox">
            <label for="tabexample2">Default Nav Element</label>
            <ul class="nav-list">
                <li><a class="nav-link">Link 1</a></li>
                <li><a class="nav-link">Link 2</a></li>
                <li><a class="nav-link active">Link 3</a></li>
                <li><a class="nav-link">Link 4</a></li>
                <li><a class="nav-link">Link 5</a></li>
                <li><a class="nav-link">Link 6</a></li>
            </ul>
        </section>
    </section>
</nav>