var interval = 0;

function NachOben()
{
 if(document.body.scrollTop)
   var y=document.body.scrollTop;
 else
   var y=window.pageYOffset;
	
   window.scrollBy(0,-10);
};

function scrollTop()
{
	clearInterval(interval);
	interval = setInterval("NachOben()",50);
};

function scrollDown()
{
	clearInterval(interval);
	interval = setInterval("NachUnten()",50);
};

function scrollStop()
{
	clearInterval(interval);
};

function nope()
{
};

function NachUnten() 
{
 if(document.body.scrollTop)
   var y=document.body.scrollTop;
 else
   var y=window.pageYOffset;
	
   window.scrollBy(0, 10);
};