$(function() 
{
	$('.scroll').each(function(){
		var id='#'+$(this).attr('id');
		var up=id+'_up';
		var down=id+'_down';
		$(up).addClass('scroll_up');
		$(down).addClass('scroll_down');
		$(up).mouseover(function(){
			startScroll(id,-1);
		});
		$(up).mouseout(function(){
			stopScroll();
		});
		$(down).mouseover(function(){
			startScroll(id,1);
		});
		$(down).mouseout(function(){
			stopScroll();
		});
	});
})

function startScroll(id,factor) {
	gIdIntervalScroll=setInterval(function(){
		var scroll=$(id).attr('scrollTop');
		scroll+=(3*factor);
		$(id).attr('scrollTop', scroll);
	},20)
}

function stopScroll() {
	if (gIdIntervalScroll != null) clearInterval(gIdIntervalScroll);
	gIdIntervalScroll = null;
}