var loop = 0;
setInterval(animate,1000);


function animate()
{
	var elem;
	var whichLayer = 'iis';
	
	if( document.getElementById ) // this is the way the standards work
	{
		elem = document.getElementById( whichLayer );
	}
	else if( document.all ) // this is the way old msie versions work
	{
		elem = document.all[whichLayer];
	}
	else if( document.layers ) // this is the way nn4 works
	{
		elem = document.layers[whichLayer];
	}
	
	loop++;
	if (loop > 6) loop = 1;
	switch(loop)
	{
	case 1:
		elem.src = 'http://spaceflight.nasa.gov/gallery/images/station/assembly/thum/s116e07154.jpg';
		break;
	case 2:
		elem.src = 'http://spaceflight.nasa.gov/gallery/images/station/assembly/thum/s114e7200.jpg';
		break;
	case 3:
		elem.src = 'http://spaceflight.nasa.gov/gallery/images/station/assembly/thum/s110e5912.jpg';
		break;
	case 4:
		elem.src = 'http://spaceflight.nasa.gov/gallery/images/station/assembly/thum/s100e5970.jpg';
		break;
	case 5:
		elem.src = 'http://spaceflight.nasa.gov/gallery/images/station/assembly/thum/s97e5009.jpg';
		break;
	case 6:
		elem.src = 'http://spaceflight.nasa.gov/gallery/images/station/assembly/thum/sts088-719-059.jpg';
		break;
	}
	
}