<html>
<head>
  <title>Div example</title>
</head>
<body>

<style type="text/css"> 
.left1 {
  float: left;
  position:absolute;
  width: 120px;
  height: 15px;
  padding: 10px;
  border: 1px solid;
  left: 50%;
  margin-left: -60px;
  top: 0px;
}

.left2 {
  float: left;
  position:absolute;
  width: 120px;
  height: 15px;
  padding: 10px;
  border: 1px solid;
  left: 50%;
  margin-left: -60px;
  top: 40px;
}  

/* "html>body" is a childselector command which means:
   select any body element that is a child of a html element.
   IE does not understand the childselector and will skip this rule.

   This is needed for Firefox. 
*/
html>body .left2 {
   top: 37px;
}
</style>

<div class="left1">
  1
</div>

<div class="left2">
  2
</div>

</body>
</html>