function chtw(lr,next,now)
{
	if (lr == 2)
	{
		$('#tw'+now).animate({opacity: 'hide', marginLeft: '50%'}, 400, function(){showtw(now,next);});
	}
	else
	{
		$('#tw'+now).animate({opacity: 'hide', marginRight: '50%'}, 400, function(){showtw(now,next);});
	}
	
}

function showtw(now,next)
{
	$('#tw'+now).attr('class','hide').css('marginLeft',0).css('marginRight',0);
	$('#tw'+next).animate({opacity: 'show'}, 500);
}