JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.6.0/jquery.min.js"></script>
<ul>
          <li class="menu"><a href="#">Server</a></li>
            <ul>
              <li class="item">
                <span>
                  <a href="#1">Start</a>
                </span>
              </li>
              <li class="item">
                <span>
                  <a href="#2">Security</a>
                </span>
              </li>
            </ul>

          <li class="menu"><a href="#">GIT</a></li>
            <ul>
              <li class="item">
                <span>
                  <a href="#1">blub</a>
                </span>
              </li>
              <li class="item">
                <span>
                  <a href="#2">wurst</a>
                </span>
              </li>
            </ul>
        </ul>

JavaScript

$(document).ready(function () {

    $(".item").hide();

    $(".menu").click(function() {

        localStorage.setItem('clickedItem', '.menu');

        $(".item").hide();

        $(this, ".item").show();

    });    
});