$(document).ready(function() {
$('#billing_phone').focusout(function() {
var phone = $(this).val();
phone = phone.replace(/[^0-9\+]/g, '');
if (phone.substr(0,4) == '+420') {
// ok
}
else if (phone.substr(0,5) == '00420') {
phone = phone.replace(/^00420/, '+420');
console.log(phone);
}
else {
phone = '+420' + phone;
}
$(this).val(phone);
});
)};