function releases_ajax_scroll(category, offset, action, big)
{
	if (big == '-big')
	{
		nb = 78;
		margin = '-2344';
		margintop = '-1172px';
	}
	else
	{
		nb = 20;
		margin = '-600';
		margintop = '-300px';
	}
	if (offset - nb < 0 && action == 'up')
		return false;
	var req = new Request.HTML({
			method: 'post',
			url: 'lib/releases_scroll_ajax.php',
			data: { 'category' : category, 'offset' : offset, 'action' : action, 'nb' : nb },
			update: $('releases-' + category + '-content-' + action),
			onComplete: function() {
				var scroll = new Fx.Tween('releases-' + category + '-wrapper', {
							duration: 700,
							transition: Fx.Transitions.Cubic.easeOut,
							onComplete: function() {
								document.getElementById('releases-' + category + '-content').innerHTML = document.getElementById('releases-' + category + '-content-' + action).innerHTML;
								document.getElementById('releases-' + category + '-wrapper').style.marginTop = margintop;
							}
							});
							if (action == 'down')
								scroll.start('margin-top', margin);
							else
								scroll.start('margin-top', '0');
				}
			}).send();
}