css3 border-radius属性详解

    #demo1 {
        width:100px;
        height:100px;
        background:red;
        border-radius: 50%;    
    }

    #demo2 {
        width:100px;
        height:50px;
        background:green;
        border-radius: 50px  50px 0 0;
             }

    #demo3 {
        width:50px;
        height:100px;
        background: pink;
        border-radius: 50px 0 0 50px;
    }

    #demo4 {
        width:100px;
        height:100px;
        background:gray ;
        border-radius: 100px 0 0 0;

    }