VAT Number Validation

One bit of code I needed recently was a way to validate a user’s VAT number, but for particular countries. Please see the reasons and method for validating a user’s VAT for most of Europe.

I used the best method of using Regex to match if the user’s entered VAT matches the pattern of the particular countries format. I have seen there are ways to get a master Regex code, but then there are some loop holes in this that some can slip through.  Therefore I opted to put in a Regex string for each country. You can see the source I used and more countries codes at this link https://www.safaribooksonline.com/library/view/regular-expressions-cookbook/9781449327453/ch04s21.html

To use the code snippet, just add it to you JavaScript code then add it to an ‘OnChange’ event on the select element with all the countries in. You can change the ‘CountryCode’ to be whatever coding system you us for countries as well, but I went for the widely used 2 digit country codes.

<selectOnChange="return Validate_VATNumber($(this).val(),$('vatField').val())">
<option value="GB">Great Britain<\option>
<option value="AT">Austria<\option>
<option value="BE">Belgium<\option>
</select>


function Validate_VATNumber(CountryCode, UsersVAT) {
    var VATreg='';

    switch (CountryCode) {
        case"GB": //Great Britain
            VATreg="^(GB)?([0-9]{9}([0-9]{3})?|[A-Z]{2}[0-9]{3})$";
            break;
        case"AT": //Austria
            VATreg="^(AT)?U[0-9]{8}$";
            break;
        case"BE": //Belgium
            VATreg="^(BE)?0[0-9]{9}$";
            break;
        case"BG": //Bulgaria
            VATreg="^(BG)?[0-9]{9,10}$";
            break;
        case"HR": //Croatia
            VATreg="";
            break;
        case"CY": //Cyprus
            VATreg="^(CY)?[0-9]{8}L$";
            break;
        case"CZ": //Czech Republic
            VATreg="^(CZ)?[0-9]{8,10}$";
            break;
        case"DK": //Denmark
            VATreg="^(DK)?[0-9]{8}$";
            break;
        case"EE": //Estonia
            VATreg="^(EE)?[0-9]{9}$";
            break;
        case"FI": //Finland
            VATreg="^(FI)?[0-9]{8}$";
            break;
        case"FR": //France
            VATreg="^(FR)?[0-9A-Z]{2}[0-9]{9}$";
            break;
        case"DE": //Germany
            VATreg="^(DE)?[0-9]{9}$";
            break;
        case"GR": //Greece
            VATreg="^(EL|GR)?[0-9]{9}$";
            break;
        case"HU": //Hungary
            VATreg="^(HU)?[0-9]{8}$";
            break;
        case"IT": //Italy
            VATreg="^(IT)?[0-9]{11}$";
            break;
        case"LV": //Latvia
            VATreg="^(LV)?[0-9]{11}$";
            break;
        case"LT": //Lithuania
            VATreg="^(LT)?([0-9]{9}|[0-9]{12})$";
            break;
        case"LU": //Luxembourg
            VATreg="^(LU)?[0-9]{8}$";
            break;
        case"MT": //Malta
            VATreg="^(MT)?[0-9]{8}$";
            break;
        case"NL": //Netherlands
            VATreg="^(NL)?[0-9]{9}B[0-9]{2}$";
            break;
        case"PL": //Poland
            VATreg="^(PL)?[0-9]{10}$";
            break;
        case"PT": //Portugal
            VATreg="^(PT)?[0-9]{9}$";
            break;
        case"RO": //Romania
            VATreg="^(RO)?[0-9]{2,10}$";
            break;
        case"SK": //Slovakia
            VATreg="^(SK)?[0-9]{10}$";
            break;
        case"SI": //Slovenia
            VATreg="^(SI)?[0-9]{8}$";
            break;
        case"ES": //Spain (exc. Canary Islands)
            VATreg="^(ES)?[0-9A-Z][0-9]{7}[0-9A-Z]$";
            break;
        case"SE": //Sweden
            VATreg="^(SE)?[0-9]{12}$";
            break;
     }

    if (VATreg .text(UsersVAT)) {
        //True
    }
    else {
        //False
    }
    returnVATreg .text(UsersVAT)
};