how to get value of id from select input and not value code example

Example 1: get selected option value jquery

$("#vacc_wellness_agegroups option:selected").val();

Example 2: jquery selected option value

$(document).ready(function(){
    $("select.country").change(function(){
        var selectedCountry = $(this).children("option:selected").val();
        alert("You have selected the country - " + selectedCountry);
    });