function getPos(obj){    var iTop = 0;    while(obj){        iTop += obj.offsetTop;        obj = obj.offsetParent;    }    return iTop;}

span{    border-top:10px dashed transparent;    border-left:10px dashed transparent;    border-right:10px dashed transparent;    border-bottom:10px solid red;    width: 0px; height: 0px; display: block;}