    <!--
      /**************************
       ** Validation functions **
       **************************/

      function schrikkelyear(year)
      {
        if((year % 4) == 0)
        {
          if((year % 100) == 0)
          {
            result = ((year % 400) == 0);
          }
          else
          {
            result = true;
          }
        }
        else
        {
          result = false;
        }
        return result;
      }


      function TrimZeroes(numstring)
      {
        while(numstring.charAt(0) == "0") numstring = numstring.substring(1);
        if(numstring == "") numstring = "0";
        return numstring;
      }

      function CheckNumberField(field,max,min,langcode)
      {    
        sNo = TrimZeroes(field.value);
        lNo = parseInt(sNo);
        sNewNo = lNo + "";
        if(field.value != "" && (sNewNo != sNo || lNo > max || lNo < min))
        {
          if(langcode == "FR")
          {
            alert(field.value + " n'est pas un numero ou est trop grand !");
          }
          else if(langcode == "NL")
          {
            alert( field.value + " is geen nummer of is te groot !");
          }
          else if(langcode == "EN")
          {
            alert(field.value + " is not a number or is too big !");
          }
          field.value="";
          return false;
        }
        else 
        {
          return true;
        }
      }

      function CheckPosNumberField(field,langcode)
      {    
        sNo = TrimZeroes(field.value);
        lNo = parseInt(sNo);
        sNewNo = lNo + "";
        if(field.value != "" && (sNewNo != sNo || lNo < 1))
        {
          if(langcode == "FR")
          {
            alert(field.value + " n'est pas un numero !");
          }
          else if(langcode == "NL")
          {
            alert( field.value + " is geen nummer !");
          }
          else if(langcode == "EN")
          {
            alert(field.value + " is not a number !");
          }
          field.value="";
          return false;
        }
        else 
        {
          return true;
        }
      }

      function CheckStringField(field,max,langcode)
      {
        if(field.value.length > max)
        {
          if(langcode == "FR")
          {
            alert(field.value + " contient trop de characters! (maximum " + max + ")");
          }
          else if(langcode == "NL")
          {
            alert(field.value + " bevat teveel tekens ! (maximaal " + max + ")");
          }
          else if(langcode == "EN")
          {
            alert(field.value + " contains too many characters ! (maximum " + max + ")");
          }
          field.value="";
          return false;
        }
        else 
        {
          return true;
        }
      }
      
      function CheckStringFieldMin(field,min,langcode)
      {
        if(field.value.length < min)
        {
          if(langcode == "FR")
          {
            alert(field.value + " contient pas assez de characters! (minimum " + min + ")");
          }
          else if(langcode == "NL")
          {
            alert(field.value + " bevat te weinig tekens ! (minimaal " + min + ")");
          }
          else if(langcode == "EN")
          {
            alert(field.value + " contains not enough characters ! (minimaal " + min + ")");
          }
          field.value="";
          return false;
        }
        else 
        {
          return true;
        }
      }      
      
      function CheckDateField(yearfield, monthfield, dayfield, langcode)
      {
        datefield = dayfield.value + "/" + monthfield.value + "/" + yearfield.value;
        if((yearfield.value == "") || (monthfield.value == "") || (dayfield.value == ""))
        {
          if((yearfield.value) || (monthfield.value) || (dayfield.value))
          {
            if(langcode == "FR")
            {
              alert(datefield + " n'est pas une date authorisée");
            }
            else if(langcode == "NL")
            {
              alert(datefield + " is geen geldige datum");
            }
            else if(langcode == "EN")
            {
              alert(datefield + " is not a valid date");
            }            
            yearfield.value = "";
            monthfield.value = "";
            dayfield.value = "";
            return false
          }
          else
          {
            return true;
          }
        }
        else
        {
          
          
          if(!(CheckNumberField(dayfield,      31, 1, langcode))) return false;
          if(!(CheckNumberField(monthfield,    12, 1, langcode))) return false;
          if(!(CheckNumberField(yearfield,   2070, 1, langcode))) return false;
          monthval = parseInt(TrimZeroes(monthfield.value));
          dayval = parseInt(TrimZeroes(dayfield.value));
          yearval = parseInt(TrimZeroes(yearfield.value));
          
          if((monthval == 4) || (monthval == 6) || (monthval == 9) || (monthval == 11))
          {
            maxday = 30;
          }
          else if(monthval == 2)
          {
            if(schrikkelyear(yearval)) maxday = 29;
            else                       maxday = 28;
          }
          else
          {
            maxday = 31;
          }
          
          if(dayval > maxday)
          {
            if(langcode == "FR")
            {
              alert(datefield + " n'est pas une date authorisée");
            }
            else if(langcode == "NL")
            {
              alert(datefield + " is geen geldige datum");
            }
            else if(langcode == "EN")
            {
              alert(datefield + " is not a valid date");
            }                        
            yearfield.value = "";
            monthfield.value = "";
            dayfield.value = "";
            return false
          }
          else
          {
            return true;
          }
        }
      }

      function CheckMandatoryField(field, fieldname, langcode)
      {
        while(field.value.charAt(field.value.length-1)==' '){
           field.value=field.value.substring(0,field.value.length-1);
        }
 
        if(field.value == "")
        {
          if(langcode == "FR")
          {
            alert(fieldname + " est obligatoire !");
          }
          else if(langcode == "NL")
          {
            alert(fieldname + " is verplicht !");
          }
          else if(langcode == "EN")
          {
            alert(fieldname + " is mandatory !");
          }         
          return false;
        }
        else 
        {
          return true;
        }
      }
      
      function CheckExclusiveMandatoryFields(field1, field1name, field2, field2name, langcode)
      {

        while(field1.value.charAt(field1.value.length-1)==' '){
           field1.value=field1.value.substring(0,field1.value.length-1);
        }
        while(field2.value.charAt(field2.value.length-1)==' '){
           field2.value=field2.value.substring(0,field2.value.length-1);
        }
 
        if((field1.value == "") && (field2.value == ""))
        {
          if(langcode == "FR")
          {
            alert(fiel1dname + " ou " + fiel2dname + " est obligatoire !");
          }
          else if(langcode == "NL")
          {
            alert(field1name + " of " + field2name + " is verplicht !");
          }
          else if(langcode == "EN")
          {
            alert(field1name + " or " + field2name + " is mandatory !");
          }          
          return false;
        }
        else 
        {
          return true;
        }
      }

      function CheckMandatoryRadio(field, fieldname, langcode)
      {
        checked = false;
        for(i = 0 ;i < field.length ; i++)
        {
          checked |= field[i].checked;
        }
        if(!checked)
        {
          if(langcode == "FR")
          {
            alert(fieldname + " est obligatoire !");
          }
          else if(langcode == "NL")
          {
            alert(fieldname + " is verplicht !");
          }
          else if(langcode == "EN")
          {
            alert(fieldname + " is mandatory !");
          }          
          return false;
        }
        else 
        {
          return true;
        }
      }

      function CheckMandatorySelect(field, fieldname, langcode)
      {
        checked = false;
        for(i = 0 ;i < field.length ; i++)
        {
          if(!field[i].value == '')
          {
            checked |= field[i].selected;
          }
        }
        if(!checked)
        {
          if(langcode == "FR")
          {
            alert(fieldname + " est obligatoire !");
          }
          else if(langcode == "NL")
          {
            alert(fieldname + " is verplicht !");
          }
          else if(langcode == "EN")
          {
            alert(fieldname + " is mandatory !");
          }                    
          return false;
        }
        else 
        {
          return true;
        }
      }
 
    //-->

    //-->