var Mac = navigator.appVersion.indexOf('Mac',0) != -1;
var Win = navigator.appVersion.indexOf('Win',0) != -1;
var IE  = navigator.appName.indexOf("Microsoft Internet Explorer",0) != -1;
var NN  = navigator.appName.indexOf("Netscape",0) != -1;
var GE  = navigator.userAgent.indexOf("Gecko") != -1;
function topposition(){
  if( IE ){
    position = document.body.scrollTop;
  } else {
    position = window.pageYOffset;
  } movePosition()
}

function movePosition(){
  position = Math.floor(position*0.8);
  if( position > 0.1 ){
    window.scrollTo(0,position)
    setTimeout("topposition()",50);
  } else { window.scrollTo(0,0) }
}