/*css style */
#up {
width:0px;
height:0px;
border-bottom:10px solid #89b007;
border-left:10px solid #fff;
border-right:10px solid #fff;
}
#down {
width:0px;
height:0px;
border-top:10px solid #89b007;
border-left:10px solid #fff;
border-right:10px solid #fff;
}
#left {
width:0px;
height:0px;
line-height:0px; /*解决ie出现梯形问题*/
border-right:10px solid #89b007;
border-top:10px solid #fff;
border-bottom:10px solid #fff;
}
#right {
width:0px;
height:0px;
line-height:0px; /*解决ie出现梯形问题*/
border-left:10px solid #89b007;
border-top:10px solid #fff;
border-bottom:10px solid #fff;
}
#trapezoid {
width:7px;
height:15px;
border-bottom:10px solid #89b007;
border-left:10px solid #fff;
border-right:10px solid #fff;
}
html：
<div id="up">
</div>
<br/>
<div id="down">
</div>
<br/>
<div id="left">
</div>
<br/>
<div id="right">
</div>
<div id="trapezoid">
</div>
