function changeprice (strselect) {
  opt_id = strselect.value;
  
  if(document.getElementById) {
    if (document.getElementById('prijs')) {
      document.getElementById('prijs').innerHTML = prijsopties[opt_id]['prijs'];
    }
    if (document.getElementById('prijsinclbtw')) {
      document.getElementById('prijsinclbtw').innerHTML = prijsopties[opt_id]['prijsinclbtw'];
    }
  }
  else if(document.all) {
    if (document.all['prijsinclbtw']) {
      document.all['prijs'].innerHTML = prijsopties[opt_id]['prijs'];
    }
    
    if (document.all['prijsinclbtw']) {
      document.all['prijsinclbtw'].innerHTML = prijsopties[opt_id]['prijsinclbtw'];
    }
  }
  else {
    if (document.layers['prijs']) {
      with(document.layers['prijs'].document){write(prijsopties[opt_id]['prijs']);close();}
    }
    if (document.layers['prijsinclbtw']) {
      with(document.layers['prijsinclbtw'].document){write(prijsopties[opt_id]['prijsinclbtw']);close();}
    }
  }
  
}


function openwin(URL, wdt, hgt, windowname){
  window.open(URL, windowname, 'toolbar=0,scrollbars=0,location=0,statusbar=0,menubar=0,resizable=0');
}