#backtotop {
  background: #F7F7F7;
  border: 1px solid #CCCCCC;
  border-radius: 5px 5px 5px 5px;
  bottom: 10px;
  color: #333333;
  cursor: pointer;
  display: none;
  height: 30px;
  line-height: 30px;
  padding: 5px 10px;
  position: fixed;
  right: 10px;
  text-align: center;
  z-index: 1;
  -moz-border-radius: 5px;
  -webkit-border-radius: 5px;
}

#backtotop:hover {
  background: #EEEEEE;
}

<!--[if lte IE 6]>
html {
  overflow-x: auto;
  overflow-y: hidden;
}

* html #backtotop {
  position:absolute;
}
<![endif]-->