效果：
代码：
html：
<div class="main">
<div class="box b1"></div>
<div class="box b2"></div>
</div>
css：
.main {
position: absolute;
top: 50%;
left: 50%;
width: 300px;
height: 300px;
transform: translate(-50%,-50%);
-webkit-perspective: 1500;
-moz-perspective: 1500;
}
.box {
position: absolute;
top: 0;
left: 0;
width: 300px;
height: 300px;
transition: all 1s;
backface-visibility: hidden;
border-radius: 10px;
cursor: pointer;
}
.b1{
background:skyblue;
}
.b2 {
background:tomato;
transform: rotateY(-180deg);
}
javascript：
var b1 = document.querySelector(".b1");
var b2 = document.querySelector(".b2");
b1.onclick = function() {
b1.style.transform = "rotateY(180deg)";
b2.style.transform = "rotateY(0deg)";
}
b2.onclick = function() {
b2.style.transform = "rotateY(-180deg)";
b1.style.transform = "rotateY(0deg)";
}
-webkit-perspective：透视效果
backface-visibility：隐藏被旋转的 div 元素的背面
