function swapInvis(id,state) {
	if (state > 0) { 
		document.getElementById(id).style.visibility='visible' 
		document.getElementById('logo').src='./images/logos/'+id+'_middel.png' }
	else { 
		document.getElementById(id).style.visibility='hidden' 
		document.getElementById('logo').src='./images/plattegrond/blank_150_150.png' }
	}