html 折叠下拉菜单

Posted 2021-05-11

.nav {
  margin-bottom: 48px;
}
.nav ul {
  *zoom: 1;
  list-style: none;
  margin: 0;
  padding: 0;
  background: #333;
}
.nav ul:before,
.nav ul:after {
  content: "";
  display: table;
}
.nav ul:after {
  clear: both;
}
.nav ul > li {
  float: left;
  position: relative;
}
.nav a {
  display: block;
  padding: 10px 20px;
  line-height: 1.2em;
  color: #fff;
  border-left: 1px solid #595959;
}
.nav a:hover {
  text-decoration: none;
  background: #595959;
}
.nav li ul {
  background: #273754;
}
.nav li ul li {
  width: 200px;
}
.nav li ul a {
  border: none;
}
.nav li ul a:hover {
  background: rgba(0, 0, 0, 0.19999999999999996);
}
/* Not Animated
============================== */
.nav1 ul > li:hover ul {
  left: 0;
}
.nav1 li ul {
  position: absolute;
  left: -9999em;
  top: 36px;
  z-index: 1;
}
/* Fade In and Out
============================== */
.nav2 ul > li:hover ul {
  visibility: visible;
  opacity: 1;
  filter: alpha(opacity=100);
}
.nav2 li ul {
  position: absolute;
  left: 0;
  top: 36px;
  z-index: 1;
  visibility: hidden;
  opacity: 0;
  filter: alpha(opacity=0);
  -webkit-transition: 200ms ease;
  -moz-transition: 200ms ease;
  -o-transition: 200ms ease;
  transition: 200ms ease;
}
/* Fold Out
============================== */
.nav5 ul > li:hover ul {
  max-height: 1000px;
  -webkit-transform: perspective(400) rotate3d(0, 0, 0, 0);
}
.nav5 li ul {
  position: absolute;
  left: 0;
  top: 36px;
  z-index: 1;
  max-height: 0;
  overflow: hidden;
  -webkit-transform: perspective(400) rotate3d(1, 0, 0, -90deg);
  -webkit-transform-origin: 50% 0;
  -webkit-transition: 350ms;
  -moz-transition: 350ms;
  -o-transition: 350ms;
  transition: 350ms;
}

		<h2>Fold Out</h2>
		<nav class="nav nav5">
			<ul>
				<li>
					<a href="#">Nav Item</a>
					<ul>
						<li><a href="#">Subnav Item</a></li>
						<li><a href="#">Subnav Item</a></li>
						<li><a href="#">Subnav Item</a></li>
					</ul>
				</li>
				<li>
					<a href="#">Nav Item</a>
					<ul>
						<li><a href="#">Subnav Item</a></li>
						<li><a href="#">Subnav Item</a></li>
						<li><a href="#">Subnav Item</a></li>
					</ul>
				</li>
				<li>
					<a href="#">Nav Item</a>
					<ul>
						<li><a href="#">Subnav Item</a></li>
						<li><a href="#">Subnav Item</a></li>
						<li><a href="#">Subnav Item</a></li>
					</ul>
				</li>
				<li>
					<a href="#">Nav Item</a>
					<ul>
						<li><a href="#">Subnav Item</a></li>
						<li><a href="#">Subnav Item</a></li>
						<li><a href="#">Subnav Item</a></li>
					</ul>
				</li>
				<li>
					<a href="#">Nav Item</a>
					<ul>
						<li><a href="#">Subnav Item</a></li>
						<li><a href="#">Subnav Item</a></li>
						<li><a href="#">Subnav Item</a></li>
					</ul>
				</li>
			</ul>
		</nav>