function showx(target_idx){
	var x50thanniv1 = document.getElementById("x50thanniv1");
	var x50thanniv1on = document.getElementById("x50thanniv1on");
	var x50thanniv1off = document.getElementById("x50thanniv1off");
	var x50thanniv2 = document.getElementById("x50thanniv2");
	var x50thanniv2on = document.getElementById("x50thanniv2on");
	var x50thanniv2off = document.getElementById("x50thanniv2off");
	var x50thanniv3 = document.getElementById("x50thanniv3");
	var x50thanniv3on = document.getElementById("x50thanniv3on");
	var x50thanniv3off = document.getElementById("x50thanniv3off");
	var x50thanniv4 = document.getElementById("x50thanniv4");
	var x50thanniv4on = document.getElementById("x50thanniv4on");
	var x50thanniv4off = document.getElementById("x50thanniv4off");
		
	var target = document.getElementById(target_idx);
	var targetOn = document.getElementById(target_idx + 'on');
	var targetOff = document.getElementById(target_idx + 'off');
	var sections = [x50thanniv1,x50thanniv2,x50thanniv3,x50thanniv4]; 
	var on_images = [x50thanniv1on,x50thanniv2on,x50thanniv3on,x50thanniv4on];
	var off_images = [x50thanniv1off,x50thanniv2off,x50thanniv3off,x50thanniv4off];
	
	for(var i = 0; i < sections.length; i++){
		if(sections[i] != target){
			sections[i].style.display = 'none';
			on_images[i].style.display = 'none';
			off_images[i].style.display = 'block';
		}
	}
	if (target.style.display == 'none') {
		target.style.display = 'block';
		targetOn.style.display = 'block';
		targetOff.style.display = 'none';
		} 
}