CSS代码：
.border_cort, .border_corr, .border_corb, .border_corl {
display: inline-block;
width:;
height:;
border-width: 6px;
overflow: hidden;
}
.border_cort {
border-color: #333 transparent transparent;
border-style: solid dotted dotted;
}
.border_corr {
border-color: transparent #333 transparent transparent;
border-style: dotted solid dotted dotted;
}
.border_corb {
border-color: transparent transparent #333;
border-style: dotted dotted solid;
}
.border_corl {
border-color: transparent transparent transparent #333;
border-style: dotted dotted dotted solid;
}
HTML代码：
<span class="border_cort"></span> //下箭头
<span class="border_corb"></span> //上箭头
<span class="border_corl"></span> //右箭头
<span class="border_corr"></span> //左箭头