var commercial;
var running = false;
var topPos = 2;
var intval;

window.onload = function()
{
	commercial = document.getElementById('commercial');

	startRoller();
}

function hideCommercial()
{
	commercial.style.display = 'none';
}

function startRoller()
{
	intval = window.setInterval("doRoll();", 2);
}

function doRoll()
{
	topPos -= 2;
	commercial.style.marginTop = topPos;

	if(topPos < -120)
	{
		window.clearInterval(intval);
	}
}