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); 
    } 
}