$(document).ready(function(){
	$('input[name="contact[want_invoice]"]').click(function(){
		setInvoiceFormVisibility();
	});
	setInvoiceFormVisibility();
});

function setInvoiceFormVisibility()
{
	var rows = $('#contact_invoice_nip').parents('tr');
	if($('input[name="contact[want_invoice]"]:checked').val() == 'yes')
	{
		$(rows[1]).show();
	}
	else
	{
		$(rows[1]).hide();
	}
}