css写出三角形（兼容IE）

css写出三角形

利用css写三角形，兼容IE7

.arrow-up {
        width:0px;
        height:0px;
        border-left:10px solid transparent;
        border-right:10px solid transparent;
        border-bottom:10px solid red;
        font-size:0px;
        line-height:0px;
        margin: 0 auto;
    } 

    .arrow-down {
        width:0px;
        height:0px;
        border-left:10px solid transparent;
        border-right:10px solid transparent;
        border-top:10px solid blue;
        font-size:0px;
        line-height:0px;
    } 

    .arrow-left {
        width:0px;
        height:0px;
        border-bottom:10px solid transparent;
        border-top:10px solid transparent;
        border-right:10px solid #DC143C;
        font-size:0px;
        line-height:0px;
    }
    .arrow-right {
        width:0px;
        height:0px;
        border-bottom:10px solid transparent;
        border-top:10px solid transparent;
        border-left:10px solid #FF00FF;
        font-size:0px;
        line-height:0px;
    }