I want to create a CSS navigation with submenus that appear when the heading tab is clicked. Here's example HTML of how I'd like to see it work:

```
<ul id="menu">
<li id="nav-1"><a href="home.php">Home</a></li>
<li id="nav-2"><a href="#">Menu 1</a>
<ul id="subnav-2">
  <li><a href="page1">Page 1</a></li>
  <li><a href="page2">Page 2</a></li>
  <li><a href="page3">Page 3</a></li>
</ul>
</li>
<li id="nav-3"><a href="#">Menu 2</a>
<ul id="subnav-3">
  <li><a href="page1">page 1</a></li>
  <li><a href="page2">page 2</a></li>
  <li><a href="page3">page 3</a></li>
</ul>
</li>
  <li id="nav-4"><a href="crickets.php">Other tab without submenu</a>
  </li>
</ul>

```

I can't seem to find anything online to make this work. Any ideas?