select option value jquery

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

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

<select id="myselect">
    <option value="1">Mr</option>
    <option value="2" selected="selected">Mrs</option>
    <option value="3">Ms</option>
    <option value="4">Dr</option>
    <option value="5">Prof</option>
</select>

<script>
  alert($( "#myselect" ).val()); //alert '2'
  //OR
  alert($( "#myselect option:selected" ).attr('value')); //alert '2'
  
  //Use this if you want to get the label and not the value
  alert($( "#myselect option:selected" ).text()); //alert 'Mrs'
</script>

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

<select id="state">
    <option value="state1" data-id="1">state1</option>
    <option value="state2" data-id="2">state2</option>
    <option value="state3" data-id="3">state3</option>
</select>

$('#state option[data-id="2"]').val();

//output state2

$('.selDiv option[value="SEL1"]')

$('.id_100 option[value=val2]').attr('selected','selected');