Setting invoice country same as shipping country in EU
This script sets the invoice country to the same country as the shipping country when a country inside EU is selected. The purpose of this is to not allow customers to select an invoice country outside EU while delivery is inside EU. This prevents customers from bypassing VAT tax on their order.

1. Navigate to Management > CMS and scroll down to Your order and click the Edit icon
2. In the text editor, click the Insert icon (the icon with square boxes) at the top right
3. Click on Edit HTML

The text editor now switches to HTML editing. If code is pasted here, the code will not go through the CMS HTML sanitizer.

Paste the following code in the page footer:

<script>
function setInvoiceCountryAsShippingCountryInEU() {

	/* https://en.wikipedia.org/wiki/European_Economic_Area
		https://ec.europa.eu/taxation_customs/vies/

		GR = greece (in VIES EL is used)
		XI - Northen Ireland ? not in EasyWebshop country list...

	*/
	var eu_countries = ['AT', 'BE', 'BG', 'CY', 'CZ', 'DE', 'DK', 'EE', 'ES', 'FI',
		'FR', 'GR', 'HR', 'HU', 'IE', 'IT', 'LT', 'LU', 'LV', 'MT',
		'NL', 'PL', 'PT', 'RO', 'SE', 'SI', 'SK'];

	// Get shipping and invoice countries from checkout form
	var shipping_country	= accountform.d_country.value;
	var invoice_country	= '';
	if (accountform.country) {
		invoice_country = accountform.country.value;
	}


	// Check if shipping and invoice country are different and if shipping is in EU
	if (shipping_country != invoice_country && eu_countries.includes(shipping_country)) {
		if (accountform.country) {
			accountform.country.value = shipping_country;

		} else {
			let country_input	= document.createElement('input');
			country_input.name	= 'country';
			country_input.value	= shipping_country;
			accountform.appendChild(country_input);
		}
	}
}

try {

	// accountform is where it all happens
	var accountform = document.getElementById('accountform');

	// Initiallly set invoice country
	setInvoiceCountryAsShippingCountryInEU();

	// Re-set invoice country on submit
	accountform.addEventListener('submit', function(e) {
		setInvoiceCountryAsShippingCountryInEU();
		al(accountform); // submit
	});

	// Also don't forget the submit link in the checkout flow
	document.getElementsByClassName('checkoutprogress')[0].childNodes[2].firstChild.addEventListener('click', function(e) {
		setInvoiceCountryAsShippingCountryInEU();
		al(accountform); // submit
	});

} catch(error) {
	console.error(error);
}
</script>

If your webshop is multilingual, the code needs to be inserted for each language individually.