Fixed box at top of window with scrolling

by leongaban

HTML

<div id="fixedContainer">
</div>
<div style="height:1000px;background-color:#bbb;"></div>

CSS

#fixedContainer
{
    background-color:#ddd;
  position: fixed;
  width: 200px;
  height: 100px;
  left: 50%;
  top: 0%;
  margin-left: -100px; /*half the width*/
}