var m_iPrevTop = 0;

function ARTMoveBgCars()
{
	var oDiv = document.getElementById('divBgCars');

	var iWindowHeight = ARTGetWindowHeight();

	var iScrollTop = ARTGetScrollTop();
	if (iScrollTop == undefined)
	{
		iScrollTop = 0;
	}

	var iTop = iScrollTop + (iWindowHeight - 300);

	if (m_iPrevTop != iTop)
	{
		oDiv.style.top = iTop + 'px';
	}

	m_iPrevTop = iTop;
}

function ARTGetScrollTop()
{
	var iScrollTop = 0;

	if (document.body.scrollTop)
	{
		iScrollTop = document.body.scrollTop;
	}
	else
	{
		iScrollTop = window.pageYOffset;
	}

	return iScrollTop;
}

function ARTGetWindowHeight()
{
	return document.body.clientHeight;
}