这是一个使用CSS3中的transition和transform两个属性制作的一个动画下拉菜单效果，整个效果未采用任何js脚本代码，其中下接的折叠效果是通过transform的rotate来实现的，而transition是用来控制动画更具线性，当然这个效果也用到了transform的3d旋转属性，感兴趣的可以围观一下。扩大你自己的视野。

demodownload

HTML CODE

<div class="box">
  <ul class="menu">
    <li><a href="#"></a></li>
    <li><a href="#">About Me</a>
    	<ul>
        <li><a href="#">Lorem ipsum dolor</a></li>
        <li><a href="#">Maecenas lacinia sem</a></li>
        <li><a href="#">Suspendisse fringilla</a></li>
    	</ul>
    </li>
    <li><a href="#">Portfolio</a>
    	<ul>
        <li><a href="#">Lorem ipsum dolor</a></li>
        <li><a href="#">Maecenas dignissim ..</a></li>
        <li><a href="#">Suspendisse fringilla</a></li>
        <li><a href="#">Lorem ipsum dolor</a></li>
        <li><a href="#">Maecenas lacinia sem</a></li>
        <li><a href="#">Suspendisse fringilla</a></li>
    	</ul>
    </li>
    <li><a href="#">Clients</a>
    	<ul>
        <li><a href="#">Lorem ipsum dolor</a></li>
        <li><a href="#">Maecenas lacinia sem</a></li>
        <li><a href="#">Suspendisse fringilla</a></li>
    	</ul>
    </li>
    <li><a href="#">Contact Me</a>
    	<ul>
        <li><a href="#">Lorem ipsum dolor</a></li>
        <li><a href="#">Maecenas dignissim ..</a></li>
        <li><a href="#">Suspendisse fringilla</a></li>
    	</ul>
    </li>
    <li><a href="#">Support</a></li>
  </ul>
</div>

CSS CODE

body {
  background-color: #f2f2f2;
}   
.box {
  margin-top: 40px;
  height: 85px;
  border-bottom: 5px solid #fff;
  background-color: #0dc2e3;
  background-image: -webkit-linear-gradient(180deg, transparent 55%, #00bfe1 45%);
  background-image: -o-linear-gradient(180deg, transparent 50%, #00bfe1 50%);
  background-image: -ms-linear-gradient(180deg, transparent 50%, #00bfe1 50%);
  background-image: linear-gradient(90deg, transparent 50%, #00bfe1 50%);
  background-size: 30px 30px;
}
.menu {
  width: 750px;
  margin: 0 auto;
  -webkit-perspective: 50px;
  -moz-perspective: 50px;
  -ms-perspective: 50px;
  perspective: 50px;
  
}
.menu > li {
  display: inline-block;
  padding-top: 48px;
  -webkit-transform-style: preserve-3d;
  -moz-transform-style: preserve-3d;
  -ms-transform-style: preserve-3d;
  transform-style: preserve-3d;
}
.menu > li > a {
  position: relative;
  display: block;
  line-height: 36px;
  color: #fff;
  font-weight: bold;
  font-size: 20px;
  padding: 0 20px;
}
.menu > li:first-child > a:before {
  position: absolute;
  left: 0;
  top: 36px;
  content: '';
  width: 1px;
  height: 1px;
  border-width: 15px 30px;
  border-style: solid;
  border-color: transparent;
  border-top-color: #4bb100;
}
.menu > li:first-child > a:after {
  font-family: 'iconminia';
  font-style: normal;
  speak: none;
  font-weight: normal;
  -webkit-font-smoothing: antialiased;
  font-size: 22px;
  content: "\21";
}
.menu > li:first-child a,
  .menu > li:first-child:hover > a,
  .menu > li:first-child:hover a:hover {
  color: #fff;
  top: 2px;
  height: 36px;
  margin-right: 10px;
  text-shadow: 0 1px 0 #3c8f00;
  border-radius: 5px 5px 0 0;
  box-shadow: 0 1px 0 #a6d980 inset;  
  background-color: #4bb100;
}
.menu > li:hover > a {
  color: #1a89c8;
  text-decoration: none;
  border-radius: 5px 5px 0 0;
  background-color: #fff;
} 
.menu ul {
  position: absolute;
  text-align: left;
  line-height: 40px;
  font-size: 14px;
  width: 200px;
  background-color: #fff;
  -webkit-transition: all 0.3s ease-in;
  -moz-transition: all 0.3s ease-in;
  -ms-transition: all 0.3s ease-in;
  transition: all 0.3s ease-in;
  -webkit-transform-origin: 0px 0px;
  -moz-transform-origin: 0px 0px;
  transform-origin: 0px 0px;
  -webkit-transform: rotateX(-90deg);
  -moz-transform: rotateX(-90deg);
  transform: rotateX(-90deg);
  -moz-backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
  backface-visibility: hidden;
}
.menu ul a {
  display: block;
  padding: 0 15px 0 10px;
  color: #1a89c8;
}
.menu > li:hover ul {
  display: block;
  -webkit-transform: rotateX(0deg);
  -moz-transform: rotateX(0deg);
  -ms-transform: rotateX(0deg);
  transform: rotateX(0deg);
}
.menu ul a:hover {
  color: #fff;
  text-shadow: 0 1px 0 #1c71a1;
  text-decoration: none;
  background-color: #218bc7;
} 
@font-face {
  font-family: 'iconminia';
  src:url('fonts/iconminia.eot');
  src:url('fonts/iconminia.eot?#iefix') format('embedded-opentype'),
   url('fonts/iconminia.svg#iconminia') format('svg'),
   url('fonts/iconminia.woff') format('woff'),
   url('fonts/iconminia.ttf') format('truetype');
  font-weight: normal;
  font-style: normal;
}

demodownload

如需转载，烦请注明出处：http://www.w3cplus.com/demo/css3-animation-menu.html