Fluid Menu是一个语义、SEO友好、可移动和多级下拉菜单插件，使用jQuery、CSS flexbox和Font Awesome标志性字体构建。

当调整窗口大小时，下拉菜单会优雅地展开和折叠菜单项，以适应不同的屏幕大小，同时保持其可用性和美观性。

如何使用它:

1.在HTML文档中加载jQuery库、Font Awesome标志性字体（本例中为v4）和Fluid Menu插件的文件。

<!-- jQuery is required -->
<script src="/path/to/cdn/jquery.slim.min.js"></script>
 
<!-- Font Awesome Icons -->
<link rel="stylesheet" href="/path/to/font-awesome.min.css" />
 
<!-- Fluid Menu Files -->
<link rel="stylesheet" href="/path/to/css/f-menu.css" />
<script src="/path/to/js/f-menu.js"></script>

2.从嵌套的导航列表中创建一个水平下拉菜单。

<div id="f-menu-horizontal">
  <nav class="menu" aria-label="Main navigation">
    <ul>
      <li class="hasChildren level-1">
        <div>
          <a href="#">Menu 1</a>
          <a href="#" class="dropdown-toggle" aria-expanded="false">
          <i class="fa fa-angle-down"></i>
          </a>
        </div>
        <ul class="sub-menu" role="group">
          <li class="level-2">
            <div>
              <a href="#">Menu 1-1</a>
            </div>
          </li>
          <li class="hasChildren level-2">
            <div>
              <a href="#">Menu 1-2</a>
              <a href="#" class="dropdown-toggle" aria-expanded="false">
              <i class="fa fa-angle-down"></i>
              </a>
            </div>
            <ul class="sub-menu" role="group">
              <li class="level-3">
                <div>
                  <a href="#">Menu 1-2-1</a>
                </div>
              </li>
              <li class="hasChildren level-3">
                <div>
                  <a href="#">Menu 1-2-1</a>
                  <a href="#" class="dropdown-toggle" aria-expanded="false">
                  <i class="fa fa-angle-down"></i>
                  </a>
                </div>
                <ul class="sub-menu">
                  <li class="level-4">
                    <div>
                      <a href="#">Menu 1-2-1-1</a>
                    </div>
                  </li>
                  <li class="level-4">
                    <div>
                      <a href="#">Menu 1-2-1-2</a>
                    </div>
                  </li>
                  <li class="level-4">
                    <div>
                      <a href="#">Menu 1-2-1-3</a>
                    </div>
                  </li>
                </ul>
              </li>
              <li class="level-3">
                <div>
                  <a href="#">Menu 1-2-2</a>
                </div>
              </li>
            </ul>
          </li>
          <li class="level-2">
            <div>
              <a href="#">Menu 1-3</a>
            </div>
          </li>
        </ul>
      </li>
      <li class="level-1">
        <div>
          <a href="#">Menu 2</a>
        </div>
      </li>
    </ul>
  </nav>
  <nav class="hamburger">
    <ul>
      <li>
        <div>
          <a href="#" class="dropdown-toggle" aria-expanded="false">
          <i class="fa fa-navicon"></i>
          </a>
        </div>
      </li>
    </ul>
  </nav>
</div>

3.从嵌套的导航列表中创建一个垂直下拉菜单。

<div id="f-menu-vertical">
  <nav class="vhamburger">
    <ul>
      <li>
        <div>
          <a href="#" class="dropdown-toggle" aria-expanded="false">
          <i class="fa fa-navicon"></i>
          </a>
        </div>
      </li>
    </ul>
  </nav>
  <nav class="menu hide" aria-label="Main navigation">
    <ul class="">
      <li class="hasChildren level-1">
        <div>
          <a class="link" href="#">Menu 1</a>
          <a href="#" class="dropdown-toggle" aria-expanded="false">
          3
          <i class="fa fa-angle-down"></i>
          </a>
        </div>
        <ul class="sub-menu" role="group">
          <li class="level-2">
            <div>
              <a class="link" href="#">Menu 1-1</a>
            </div>
          </li>
          <li class="hasChildren level-2">
            <div>
              <a class="link" href="#">Menu 1-2</a>
              <a href="#" class="dropdown-toggle" aria-expanded="false">
              4
              <i class="fa fa-angle-down"></i>
              </a>
            </div>
            <ul class="sub-menu" role="group">
              <li class="level-3">
                <div>
                  <a class="link" href="#">Menu 1-2-1</a>
                </div>
              </li>
              <li class="hasChildren level-3">
                <div>
                  <a class="link" href="#">Menu 1-2-2</a>
                  <a href="#" class="dropdown-toggle" aria-expanded="false">
                  3
                  <i class="fa fa-angle-down"></i>
                  </a>
                </div>
                <ul class="sub-menu">
                  <li class="level-4">
                    <div>
                      <a class="link" href="#">Menu 1-2-2-1</a>
                    </div>
                  </li>
                  <li class="level-4">
                    <div>
                      <a class="link" href="#">Menu 1-2-2-2</a>
                    </div>
                  </li>
                  <li class="level-4">
                    <div>
                      <a class="link" href="#">Menu 1-2-2-3</a>
                    </div>
                  </li>
                </ul>
              </li>
              <li class="level-3">
                <div>
                  <a href="#">Menu 1-2-3</a>
                </div>
              </li>
            </ul>
          </li>
          <li class="level-2">
            <div>
              <a href="#">Menu 1-2</a>
            </div>
          </li>
        </ul>
      </li>
      <li class="level-1">
        <div>
          <a href="#">Menu 2</a>
        </div>
      </li>
      <li class="level-1">
        <div>
          <a href="#">Menu 3</a>
        </div>
      </li>
      // ...
    </ul>
  </nav>
</div>

预览截图

jQuery和CSS Flexbox 响应式下拉菜单 Fluid菜单