用bootstrap和css3制作按钮式下拉菜单
利用bootstrap框架的字体图标和下拉菜单效果，以及css3的动画效果，可以做出比较优雅的按钮式下拉菜单样式
<style>
.myBtnStyle .dropdown-menu span{
margin:5px;
}
.myBtnStyle .dropdown-menu {
animation: 0.5s linear fadeIn; //css3新特性animation
}
@keyframes fadeIn { //通过keyframes规则创建动画特效，原理为将一套css样式逐渐转化成另一种css样式
0%{opacity:0;transform: translateY(-20);}
100%{opacity: 1;transform: translateY(0);}
}
</style>
</head>
<body>
<div class="container">
<div class="dropdown myBtnStyle open">
<button class="btn btn-default dropdown-toggle" data-toggle="dropdown">
explotion
</button>
<ul class="dropdown-menu">
<li><a href="#">
<span class="glyphicon glyphicon-headphones"></span> //span标签包裹的字体图标
moving</a></li>
<li><a href="#">
<span class="glyphicon glyphicon-headphones"></span>
raging</a></li>
<li><a href="#">
<span class="glyphicon glyphicon-headphones"></span>
daniangmener</a></li>
<li><a href="#">
<span class="glyphicon glyphicon-headphones"></span>
holy</a></li>
</ul>
</div>
</div>
</body>