function hide () {
	if (document.getElementById("overig")){
		var id = "hide";
		var a = document.getElementById("overig").value;
		var b = document.getElementById("gebied").value;
		if (a == "" && !(b == 9)){
			document.getElementById(id).style.display = "none";
		}
		if (!(a == "")){
			document.getElementById("gebied").value = 9;
		}
	}
}

function unhide () {
	var id = "hide";
	var a = document.getElementById("gebied").selectedIndex;
	if (a == 8){
		document.getElementById(id).style.display = "block";
	} else {
		document.getElementById(id).style.display = "none";
	}
}