function selectionChanged()
{
  if (document.getElementById("Klantpc").selectedIndex == 0)
    document.getElementById("Huisnr").value = "2";
  else
  {
    if (document.getElementById("Klantpc").selectedIndex == 1)
      document.getElementById("Huisnr").value = "20";
    else  
      document.getElementById("Huisnr").value = "21";
  }
}
  
function getDateString(y_obj, m_obj, d_obj) 
{ 
  var y = y_obj.options[y_obj.selectedIndex].value; 
  var m = m_obj.options[m_obj.selectedIndex].value; 
  var d = d_obj.options[d_obj.selectedIndex].value; 
  if (y == "" || m == "") 
  { 
    return null; 
  } 
  if (d == "") 
  { 
    d = 1; 
  } 
  return str = y + '-' + m + '-' + d; 
}