var aantal = 2;

function addfields(){
	document.getElementById(aantal).className = "visible"; 
	document.getElementById("aantal_i").value = aantal;
	
	aantal++;
}
function vizibly_div(id){
	
	if(document.getElementById(55).checked == true){
		document.getElementById(id).className = "visible_c"; 
	}else{
		document.getElementById(id).className = "not_visible"; 
	}
}