button标签点击实现数量加减

.dp_top_amount button{
float: left;
width:20px;
height:22px;
cursor: pointer;
background:#fff;
border:1px solid #ccc;
}
.dp_top_amount input{
float: left;
height:20px;
width:36px;
line-height:20px;
vertical-align: middle;
text-align: center;
border-left: none;
border-right: none;
border:1px solid #ccc;
}

<divclass="dp_top_amount">
<span>数量</span>
<buttontype="button">-</button>
<inputtype="text"/>
<buttontype="button">+</button>
</div>