css3 box-sizing属性

<style type="text/css">
            div{
                height:100px;
                width: 100px;
                padding:10px;
                border: 5px solid #000000;
                color:red;
                font-size: 14px;
                text-align: center;
            }
            .content-box{
                box-sizing: content-box;
            }
            .border-box{
                box-sizing: border-box;
            }
        </style>