Responsive Multi-level Dropdown Menu with jQuery and CSS3

A fully responsive, mobile-friendly, multi-level drop down menu made using jQuery, Html5, JavaScript and several CSS3 properties.

How to use it:

1. Create a nested nav list for the multi-level dropdown menu.

<nav id="menu-wrap">
<ul id="menu">
  <li><a href="#">Home</a></li>
  <li><a href="#">About</a></li>
  <li>
    <a href="#">Services</a>
    <ul>
      <li><a href="#">Web Design</a>
        <ul>
          <li><a href="#">HTML/CSS</a></li>
          <li><a href="#">Flash</a></li>
          <li><a href="#">Graphic Design</a></li>
        </ul>
      </li>
      <li><a href="#">Web Programming</a>
        <ul>
          <li><a href="#">PHP</a></li>
          <li><a href="#">Ruby on Rails</a></li>
          <li><a href="#">Python</a></li>
        </ul>
      </li>
      <li><a href="#">Web Hosting</a></li>
      <li><a href="#">SEO</a></li>
    </ul>
  </li>
  <li><a href="#">Projects</a>
    <ul>
      <li><a href="#">Project 1</a></li>
      <li><a href="#">Project 2</a></li>
      <li><a href="#">Project 3</a></li>
      <li><a href="#">Project 4</a></li>
    </ul>
  </li>
  <li><a href="#">Contact</a></li>
</ul>
</nav>

2. Style the dropdown menu in the CSS.

#menu, #menu ul {
  margin: 0px;
  padding: 0px;
  list-style: none;
}

#menu {
  width: 90%;
  margin: 60px auto;
  border: 1px solid #107677;
  background: #111;
  background: linear-gradient(#1ebdbe, #107677);
  border-radius: 6px;
  box-shadow: 0px 2px 2px #ccc;
}

#menu:before, #menu:after {
  content: "";
  display: block;
}

#menu:after { clear: both; }

#menu li {
  float: left;
  background: url(../images/sep.png) no-repeat;
  position: relative;
}

#menu a {
  float: left;
  padding: 12px 30px;
  color: #fff;
  text-decoration: none;
  text-transform: uppercase;
  font: bold 12px Arial, Helvetica;
}

#menu ul {
  margin: 20px 0px 0px 0px;
  opacity: 0;
  visibility: hidden;
  position: absolute;
  top: 38px;
  left: 0px;
  z-index: 1;
  background: linear-gradient(#1ebdbe, #107677);
  box-shadow: 0px -1px 0px rgba(255, 255, 255, .3);
  border-radius: 3px;
  transition: all .2s ease-in-out;
}

#menu li:hover > ul {
  opacity: 1;
  visibility: visible;
  margin: 0px;
}

#menu ul ul {
  top: 0px;
  left: 150px;
  margin: 0px 0px 0px 20px;
  box-shadow: 0px -1px 0px rgba(255, 255, 255, .3);
}

#menu ul a {
  padding: 10px;
  width: 130px;
  display: block;
  white-space: nowrap;
  float: none;
  text-transform: none;
}

#menu ul a:hover { background: linear-gradient(#1ebdbe, #107677); }

#menu ul li:first-child > a:after {
  content: '';
  position: absolute;
  left: 40px;
  top: -6px;
  border-left: 6px solid transparent;
  border-right: 6px solid transparent;
  border-bottom: 6px solid #1ebdbe;
}

#menu ul ul li:first-child > a:after {
  left: -12px;
  top: 50%;
  margin-top: -6px;
  border-top: 6px solid transparent;
  border-right: 6px solid #107677;
  border-bottom: 6px solid transparent;
}

#menu-trigger { /* hide initially */
display: none; }

3. Make the dropdown menu more user-friendly on mobile devices (screen size less than 700px).

@media(max-width: 700px) {

#menu-wrap { position: relative; }

#menu-wrap* { box-sizing: border-box; }

#menu-trigger {
  display: block;
  height: 40px;
  line-height: 40px;
  cursor: pointer;
  padding: 0px 0px 0px 35px;
  border: 1px solid #107677;
  color: #fff;
  font-weight: bold;
  background-color: #111;
  background: url(../images/menu.png) no-repeat 10px center, linear-gradient(#1ebdbe, #107677);
  border-radius: 6px;
}

#menu {
  margin: 0px;
  padding: 10px;
  position: absolute;
  top: 40px;
  width: 100%;
  z-index: 1;
  display: none;
  box-shadow: none;
}

#menu:after {
  content: '';
  position: absolute;
  left: 25px;
  top: -8px;
}

#menu ul {
  position: static;
  visibility: visible;
  opacity: 1;
  margin: 0px;
  background: none;
  box-shadow: none;
}

#menu ul ul {
  margin: 0px 0px 0px 20px;
  box-shadow: none;
}

#menu ul ul li:first-child > a:after {
  border-top: 0px;
  border-bottom: 0;
}

#menu li {
  position: static;
  display: block;
  float: none;
  border: 0px;
  margin: 5px;
  box-shadow: none;
  background: none !important;
}

#menu ul li {
  margin-left: 20px;
  box-shadow: none;
}

#menu a {
  display: block;
  float: none;
  padding: 0px;
  color: #fff;
}

#menu a:hover { color: #fafafa; }

#menu ul a {
  padding: 0px;
  width: auto;
}

#menu ul a:hover { background: none !important; }
}

4. Add the needed jQuery library to your web page.

<script src="jquery.min.js"></script>

5. Append a toggle button to the dropdown menu on mobile devices.

$('#menu-wrap').prepend('<div id="menu-trigger">Menu</div>');

6. Enable the menu toggle button

$('#menu-trigger').on('click', function(){
  $('#menu').slideToggle();
});

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This awesome jQuery plugin is developed by colleenmcguckin. For more Advanced Usages, please check the demo page or visit the official website.