function goPrevMonth(month, year) {
  //Als de maand januari is verinder met 1
  if(month == 1) {
    --year;
    month = 13;
  }
  document.location.href = '/verhuur/?month='+(month-1)+'&year='+year;
}
function goNextYear(month, year) {
  ++year;
  document.location.href = '/verhuur/?month='+ month +'&year='+year;
}
function goPrevYear(month, year) {
    --year;
  document.location.href = '/verhuur/?month='+ month +'&year='+year;
}
function goNextMonth(month, year) {
  //Als de maand december is vermeerder met 1
  if(month == 12) {
    ++year;
    month = 0;
  }
  document.location.href = '/verhuur/?month='+(month+1)+'&year='+year;
}

function changePicture(url, titel, tekst) {
	detailpic = document.getElementById('pic');
	detailpic.src=url;
	document.getElementById('fototitel').innerHTML = titel;
	document.getElementById('fotocomment').innerHTML = tekst;	
}

function confirmform()	{
	var agree = confirm("Wissen ?");
	if (agree)
		return true;
	else
		return false;
}