function validate(type){
 if (type == "pers") var validateFields = new Array('naam', 'medium', 'postadres', 'postcode', 'woonplaats', 'email');
  if (type == "deelname") var validateFields = new Array('bedrijf', 'activiteiten', 'adres', 'postcode', 'woonplaats', 'email');
  if (type == "shop") var validateFields = new Array('naam', 'voornaam', 'straat', 'huisnummer', 'postcode', 'woonplaats', 'email');

  var validated = true;
  var item;

  for (var i=0; i < validateFields.length; i++){
    if (document.getElementById) {
      item = document.getElementById(validateFields[i]);
    } else if (document.all) {
      item = document.all[validateFields[i]];
    } else if (document.layers) {
      item = document.layers[validateFields[i]];
    }


    item.style.background = "#FFFFFF";

    if (item.name == 'postcode')
    {
      $test = /^[0-9]{4}(\s*?)[A-Za-z]{2}$/.test(item.value);
      if (!$test){
        item.style.background = "#C3EFFF";
        validated = false;
      }

    } else if (item.name == 'email') {

      $test = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/.test(item.value);
      if (!$test){
        item.style.background = "#C3EFFF";
        validated = false;
      }

    } else if (item.value == ''){
         item.style.background = "#C3EFFF";
         validated = false;
    }
  }

  if (!validated) {
    document.getElementById('mailerror').style.display = "block";
  } else {
     document.getElementById('mailerror').style.display = "none";
  }

  return validated;
}