Country Code JS version 2 make changes default country+code

country_code_js_v2

<script src='https://intl-tel-input.com/node_modules/intl-tel-input/build/js/intlTelInput.js?1549804213570'></script>
<script>
// International telephone format
// $("#phone").intlTelInput();
// get the country data from the plugin
var countryData = window.intlTelInputGlobals.getCountryData(),
  input = document.querySelector("#phone"),
  addressDropdown = document.querySelector("#country");

// init plugin
var iti = window.intlTelInput(input, {
  hiddenInput: "full_phone",
  utilsScript: "https://intl-tel-input.com/node_modules/intl-tel-input/build/js/utils.js", // just for formatting/placeholders etc
  initialCountry: "au" // for country, you can change it for default
});

// populate the country dropdown
for (var i = 0; i < countryData.length; i++) {
  var country = countryData[i];
  var optionNode = document.createElement("option");
  optionNode.value = country.iso2;
  var textNode = document.createTextNode(country.name);
  optionNode.appendChild(textNode);
  addressDropdown.appendChild(optionNode);
}
// set it's initial value
addressDropdown.value = iti.getSelectedCountryData().iso2;

// listen to the telephone input for changes
input.addEventListener('countrychange', function(e) {
  addressDropdown.value = iti.getSelectedCountryData().iso2;
});

// listen to the address dropdown for changes
addressDropdown.addEventListener('change', function() {
  iti.setCountry(this.value);
});
</script>
<script>
//Append Value To Phone Field
$("#phone").prop('value', '+61 '); //for country code, you can change it for default
</script>

Source: https://stackoverflow.com/questions/57406132/intl-tel-input-change-dropdown-dialcode-from-another-dropdown