Code snippet for Shopify Plus checkout.liquid theme file to capture and validate VAT numbers and set business customers as tax exempt when applicable. Used by Sufio for Shopify app (www.sufio.com/shopify). Read more at http://sufio.com/articles/shopify/selling/vat-eu-customers-shopify/vat-exempt-eu/

shopify-checkout-vat-exempt.html

<!-- Shopify checkout -- capture and validate VAT numbers and set business customers as tax exempt when applicable. Used by Sufio for Shopify (www.sufio.com/shopify). -->
<div class="additional-checkout-fields" style="display:none">
  <div class="field field--optional field--vat-number">
    <div class="field__input-wrapper">
      <label class="field__label" for="checkout_vat_number">VAT number</label>
      <input placeholder="VAT number" autocomplete="vat number" data-backup="checkout_vat_number" class="field__input" aria-labelledby="error-for-vat_number" size="30" type="text" name="checkout[vat_number]" id="checkout_vat_number">
    </div>
  </div>
</div>

<script type="text/javascript">
  if (window.jQuery) {
  	jquery = window.jQuery;
  } else if (window.Checkout && window.Checkout.$) {
    jquery = window.Checkout.$;
  }
  
  jquery(function() {
    if (jquery('.section--shipping-address .section__content .fieldset').length) {
      var vat_number_field = jquery('.field--vat-number');
      jquery('.section--shipping-address .section__content .fieldset').append(vat_number_field);
      
      var form = jquery('.section--shipping-address .section__content .fieldset').parents('form');
      
      jquery('button[type=submit]', form).one("click", function() {    
        var email = jquery('input[name="checkout[email]"]').val();
        var vat_no = jquery('input[name="checkout[vat_number]"]').val();
        if ((email) && (vat_no)) {
            jquery.ajax({
                type : "GET",
                dataType: "jsonp",
                url: "{{ shop.url }}/apps/sufio/customer-vat/",
                data: { email: email, vat_no: vat_no },
                success: function(data) {
                    // Proceed to the next step after successfully sending the VAT number
                    jquery('button[type=submit]', form).click();
                }
            });
        } else {
            return true;
        }

        // Proceed to the next step after one second
        setTimeout( function () { 
            jquery('button[type=submit]', form).click();
        }, 1000);

        return false;
    });
    }
  });
</script>