function getPosition()
{
    if (document.documentElement.offsetHeight <= document.documentElement.scrollHeight)
	{
		var start, end, scale, term;
		start = parseInt (document.getElementById('rollingTop').style.top, 10);
		end   = parseInt (document.documentElement.offsetHeight * (2/3)) + document.documentElement.scrollTop;//, 10);// + document.body.rollingTop;// + document.documentElement.rollingTop;
		term  = 1000;
	
		if ( start != end ) 
		{
			//scale = Math.ceil( Math.abs( end - start ) / 20 );
			scale = Math.ceil( Math.abs( end - start ) / 20 );
			if ( end < start )	scale = -scale;
			document.getElementById('rollingTop').style.top = parseInt (document.getElementById('rollingTop').style.top, 10)+ scale + "px";
			term = 1;
		}
		document.getElementById('rollingTop').style.display = 'block';
	}
	
	if (document.documentElement.offsetHeight >= document.documentElement.scrollHeight)
	{
		document.getElementById('rollingTop').style.display = 'none';
	}
	//
	//alert('^^');
	setTimeout ("getPosition()", term);
}

function moveBanner() {
    document.getElementById('rollingTop').style.top = 0 + "px";
	getPosition();
	return true;
}

moveBanner();