div+css 画三角形

<style type="text/css">
.rightdirection
{
    width:0;height:0;
    line-height:0;
    border-width:20px;
    border-style:solid;
    border-color:transparent transparent transparent #A9DBF6;
}
.bottomdirection
{
    width:0;height:0;
    line-height:0;
    border-width:20px;
    border-style:solid;
    border-color: #A9DBF6 transparent transparent transparent;
}
.leftdirection
{
    width:0;height:0;
    line-height:0;
    border-width:20px;
    border-style:solid;
    border-color: transparent #A9DBF6  transparent transparent;
}
.topdirection
{
    width:0;height:0;
    line-height:0;
    border-width:20px;
    border-style:solid;
    border-color: transparent transparent #A9DBF6 transparent;
}
.topdirection1
{
    width:0;height:0;
    line-height:0;
    border-width:20px;
    border-style:solid;
    border-color: #A9DBF6   transparent transparent #A9DBF6 ;
}
</style>
<div  class="rightdirection"></div>
<p>
<div  class="bottomdirection"></div>
<p>
<div  class="leftdirection"></div>
<p>
<div  class="topdirection"></div>  

<br/><br/><br/><br/>
<div  class="topdirection1"></div>