JSFiddle - React, Tailwind, and code Playground

by Vasil Svetoslavov

HTML

<script src="https://code.jquery.com/jquery-3.4.1.slim.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.16.0/umd/popper.js"></script>
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.css">
<script src="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.3.7/js/bootstrap.min.js"></script>
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.3.7/css/bootstrap.min.css">
<!-- 
  Bootstrap docs: https://getbootstrap.com/docs
-->
<nav class="navbar navbar-default navbar-fixed-top">
  <div class="container-fluid">
    <div class="navbar-header">
      <a class="navbar-brand" href="#" onclick="return false;">
        <strong>Saturn V</strong>
      </a>
    </div>
    <div class="collapse navbar-collapse">
      <ul class="nav navbar-nav">
        <li class="dropdown">
          <a href="#" class="dropdown-toggle" data-toggle="dropdown" role="button" aria-haspopup="true" aria-expanded="false">Dropdown <span class="caret"></span></a>
          <ul class="dropdown-menu">
            <li class="dropdown-submenu">
              <a href="#" class="dropdown-toggle" data-toggle="dropdown" role="button" aria-haspopup="true" aria-expanded="false"> <span class="nav-label">Item with submenu</span></a>
              <ul class="dropdown-menu">
                <li><a href="#">Service C1</a></li>
                <li><a href="#">Service C2</a></li>
                <li><a href="#">Service C3</a></li>
                <li><a href="#">Service C4</a></li>
                <li><a href="#">Service C5</a></li>
              </ul>
            </li>
            <li><a href="#" onclick="return false;">Test</a></li>
            <li><a href="#" onclick="return false;">Test</a></li>
            <li><a href="#" onclick="return false;">Test</a></li>
            <li><a href="#" onclick="return false;">Test</a></li>
            <li><a href="#" onclick="return false;">Test</a></li>
    ...

CSS

.dropdown-menu-scrollable{
    max-height: 400px;
    overflow-y: auto;
}

.dropdown-menu-scroll-page {
  overflow-y: visible;
  max-width: 900000px;
}

.dropdown-menu {
  overflow-x: visible;
  white-space: nowrap;
}

.dropdown-submenu {
    position: relative;
}
.dropdown-submenu>.dropdown-menu.more {
  top: auto;
  bottom: -6px;
  margin-top: 0;
}
.dropdown-submenu>.dropdown-menu {
    top: 0;
    left: 100%;
    margin-top: -6px;
    margin-left: -1px;
    -webkit-border-radius: 0 6px 6px 6px;
    -moz-border-radius: 0 6px 6px;
    border-radius: 0 6px 6px 6px;
}

.dropdown-submenu:hover>.dropdown-menu {
    display: block;
}

.dropdown-submenu>a:after {
    display: block;
    content: " ";
    float: right;
    width: 0;
    height: 0;
    border-color: transparent;
    border-style: solid;
    border-width: 5px 0 5px 5px;
    border-left-color: #ccc;
    margin-top: 5px;
    margin-right: -10px;
}

.dropdown-submenu:hover>a:after {
    border-left-color: #fff;
}

.dropdown-submenu.pull-left {
    float: none;
}

.dropdown-submenu.pull-left>.dropdown-menu {
    left: -100%;
    margin-left: 10px;
    -webkit-border-radius: 6px 0 6px 6px;
    -moz-border-radius: 6px 0 6px 6px;
    border-radius: 6px 0 6px 6px;
}