1PX直线

<style type="text/css">
<!--
hr{
 border:0px;
 border-bottom:1px red dashed;
 height:1px;
}
#line1 {
       background-color: #000000;
    height:1px;
    overflow:hidden;
}
#line2{
 border-top:1px solid #000;
}
-->
</style>
<div id="line1"></div>
dfdfd
<div id="line2"></div>
dfdf
<hr />

dfdfd

dfdf

---