function toggle(x,y,z,u) {
	dv1 = document.getElementById(x);
	dv1.style.visibility = "visible";
	dv2 = document.getElementById(y);
	dv2.style.visibility = "hidden";
	dv3 = document.getElementById(z);
	dv3.style.visibility = "hidden";
	dv4 = document.getElementById(u);
	dv4.style.visibility = "hidden";
	
	
	if (x == 'portfolio1' || x == 'portfolio2') {
		liz = document.getElementById('lizzard');
		liz.style.visibility = "hidden";
	}
	
	if (x == 'home' || x == 'contact') {
		liz = document.getElementById('lizzard');
		liz.style.visibility = "visible";
	}
}