请问.box中position:relative的作用是什么呢
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; /*就是这里*/
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;
}去掉就没法用了，这里到底是起到什么作用呢？
