window.onload = positionMovie;
function positionMovie()
{
  var winW, winH;
  if (parseInt(navigator.appVersion)>3) {
    if (navigator.appName == "Netscape") {
      winW = window.innerWidth;
      winH = window.innerHeight;
    }
    if (navigator.appName.indexOf("Microsoft") != -1) {
      winW = document.body.offsetWidth;
      winH = document.body.offsetHeight;
    }
  }
  var viewer = document.getElementById('viewer');
  viewer.style.left = (winW-550)/2+'px';
  viewer.style.visibility='visible';
}