在慕课网上有篇css3学习课程，在里面看到了一种只要css3就可以完成的选中改变样式的例子，在这里记录下来。
html
<form action="#">
<div class="wrapper">
<div class="box">
<input type="radio" checked="checked" id="boy" name="1" /><span></span>
</div>
<label for="boy">男</label>
</div>
<div class="wrapper">
<div class="box">
<input type="radio" id="girl" name="1" /><span></span>
</div>
<label for="girl">女</label>
</div>
</form>
css3
form {
border: 1px solid #ccc;
padding: 20px;
width: 300px;
margin: 30px auto;
}
.wrapper {
margin-bottom: 10px;
}
.box {
display: inline-block;
width: 30px;
height: 30px;
margin-right: 10px;
position: relative;
background: orange;
vertical-align: middle;
border-radius: 100%;
}
.box input {
opacity: 0;
position: absolute;
top:0;
left:0;
width: 100%;
height:100%;
z-index:100;/*使input按钮在span的上一层，不加点击区域会出现不灵敏*/
}
.box span {
display: block;
width: 10px;
height: 10px;
border-radius: 100%;
position: absolute;
background: #fff;
top: 50%;
left:50%;
margin: -5px 0 0 -5px;
z-index:1;
}
input[type="radio"] + span {
opacity: 0;
}
input[type="radio"]:checked + span {
opacity: 1;
}
效果图
