function backToTop() { 
 var x1 = x2 = x3 = 0; 
 var y1 = y2 = y3 = 0; 
 if (document.documentElement) { 
  x1 = document.documentElement.scrollLeft || 0; 
  y1 = document.documentElement.scrollTop || 0; 
 } 
 if (document.body) { 
  x2 = document.body.scrollLeft || 0; 
  y2 = document.body.scrollTop || 0; 
 } 
 x3 = window.scrollX || 0; 
 y3 = window.scrollY || 0; 
 var x = Math.max(x1, Math.max(x2, x3)); 
 var y = Math.max(y1, Math.max(y2, y3)); 
 window.scrollTo(Math.floor(x / 2), Math.floor(y / 2)); 
 if (x > 0 || y > 0) { 
  window.setTimeout("backToTop()", 25); 
 } 
}