function MM_validateForm() { //v4.0
  var i,p,q,nm,test,num,min,max,errors='',args=MM_validateForm.arguments;
  for (i=0; i<(args.length-2); i+=3) { test=args[i+2]; val=MM_findObj(args[i]);
    if (val) { nm=val.name; if ((val=val.value)!="") {
      if (test.indexOf('isEmail')!=-1) { p=val.indexOf('@');
        if (p<1 || p==(val.length-1)) errors+='- U heeft geen geldig email adres opgegeven.\n';
      } else if (test!='R') { num = parseFloat(val);
        if (isNaN(val)) errors+='- '+nm+' U heeft geen geldig telefoonnummer opgegeven.\n';
        if (test.indexOf('inRange') != -1) { p=test.indexOf(':');
          min=test.substring(8,p); max=test.substring(p+1);
          if (num<min || max<num) errors+='- '+nm+' must contain a number between '+min+' and '+max+'.\n';
    } } } else if (test.charAt(0) == 'R') errors += '- '+nm+' is verplicht.\n'; }
  } if (errors) alert('The following error(s) occurred:\n'+errors);
  document.MM_returnValue = (errors == '');
}
//-->

function HideQuestions()
{
  var o;
  o = document.getElementById('divZoekterm1').style.display='none';
  o = document.getElementById('divZoekterm2').style.display='none';
  o = document.getElementById('divLink1').style.display='none';
  o = document.getElementById('divLink2').style.display='none';
  o = document.getElementById('divAdvertentie1').style.display='none';
  o = document.getElementById('divAdvertentie2').style.display='none';
  o = document.getElementById('divArtikelTijdschrift1').style.display='none';
  o = document.getElementById('divArtikelTijdschrift2').style.display='none';
  o = document.getElementById('divAdvertentieTijdschrift1').style.display='none';
  o = document.getElementById('divAdvertentieTijdschrift2').style.display='none';
  o = document.getElementById('divBeurs1').style.display='none';
  o = document.getElementById('divBeurs2').style.display='none';
  o = document.getElementById('divAnders1').style.display='none';
  o = document.getElementById('divAnders2').style.display='none';
}

function ShowDiv(n)
{
  var d = document.getElementById(n + '1');
  d.style.display='';
  var d = document.getElementById(n + '2');
  d.style.display='';
}

function ShowQuestion()
{
  HideQuestions();
  switch (document.frmContact.HoeGevonden.selectedIndex)
  {
    case 2: ShowDiv('divZoekterm'); break;
    case 3: ShowDiv('divLink'); break;
    case 4: ShowDiv('divAdvertentie'); break;
    case 5: ShowDiv('divArtikelTijdschrift'); break;
    case 6: ShowDiv('divAdvertentieTijdschrift'); break;
    case 7: ShowDiv('divBeurs'); break;
    case 8: ShowDiv('divAnders'); break;
  }
}