var iCurrent = 0;

function step(iNum) {
	
	var oPhotos = document.getElementById("photos").getElementsByTagName("div");
	var oTagline = document.getElementById("tagline").getElementsByTagName("div");
	
	oPhotos[iCurrent].style.display = "none";
	oTagline[iCurrent].style.display = "none";
	
	if (iNum == 0 && iCurrent > 0) {			
		iCurrent--;
	} else if (iCurrent == 0 && iNum == 0) {
		iCurrent = oPhotos.length - 1;
	} else if (iCurrent < oPhotos.length - 1 && iNum == 1) {
		iCurrent++;
	} else if (iCurrent == oPhotos.length - 1 && iNum == 1) {
		iCurrent = 0;
	}
	
	oPhotos[iCurrent].style.display = "block";
	oTagline[iCurrent].style.display = "block";
	
}