var scrnX = screen.availWidth;
var carCount = 1;

addLoadEvent(moveCar);

function moveCar()
{
	var ElCar = document.getElementById('car');
	var carX = ElCar.offsetLeft;

	if(carX > scrnX)
	{
		clearTimeout(animateCar)
	}
	else
	{
		if(carCount == 1)
		{
			swapDiv('wheel1b', 'wheel1');
			swapDiv('wheel2b', 'wheel2');

			carCount = 2;
		}
		else
		{
			swapDiv('wheel1', 'wheel1b');
			swapDiv('wheel2', 'wheel2b');

			carCount = 1;
		}		
	}

	var animateCar = setTimeout("document.getElementById('car').style.pixelLeft+=2; moveCar()", 10);
}

function swapDiv(elOn, elOff)
{
	document.getElementById(elOff).style.display = 'none';
	document.getElementById(elOn).style.display = 'block';
}