function show(welke) {
	hideAll();
	document.getElementById(welke).style.display = 'block';
}

function hideAll() {
	for(i=0;i<document.getElementsByTagName("div").length;i++){
		var elA = document.getElementsByTagName("div")[i];
		if (elA.getAttribute("id").substring(0,3) == 'sub') {
			elA.style.display = 'none';
		}
	}
}