theLayerPos = Math.round((screen.Width - 600)/2);
if (parseInt(navigator.appVersion)>3) {
 if (navigator.appName=="Netscape") {
  theLayerPos = Math.round((window.innerWidth - 600)/2);
 }
 if (navigator.appName.indexOf("Microsoft")!=-1) {
  winW = document.body.offsetWidth;
  theLayerPos = Math.round((document.body.offsetWidth - 600)/2);
 }
}
document.getElementById("theLayer").style.left = theLayerPos+"px";