window.addEvent('domready',function() {

$('gototop').setStyle('opacity','0');

new SmoothScroll();

var Change = new Fx.Style('gototop', 'opacity', {duration:250});

var scroll = window.getScrollTop();

if (scroll > 500){

    if ($('gototop').getStyle('opacity','0') == 0){Change.start(1);$('gototop').setStyle('display','');}

}

});

window.addEvent('scroll',function(e) {

var scroll = window.getScrollTop();

var Change = new Fx.Style('gototop', 'opacity', {duration:250});

function Show(){ $('gototop').setStyle('display','');}

function Hide(){ setTimeout("$('gototop').setStyle('display','none')",250);}

if (scroll > 500){

    if ($('gototop').getStyle('opacity','0') == 0){Show();Change.start(1);}

} else {

    if ($('gototop').getStyle('opacity','1') == 1){Change.start(0);Hide();}

}

});