1$( "#myselect option:selected" ).val();

1$("#vacc_wellness_agegroups option:selected").val();

1<select id="myselect">
2    <option value="1">Mr</option>
3    <option value="2" selected="selected">Mrs</option>
4    <option value="3">Ms</option>
5    <option value="4">Dr</option>
6    <option value="5">Prof</option>
7</select>
8
9<script>
10  alert($( "#myselect" ).val()); //alert '2'
11  //OR
12  alert($( "#myselect option:selected" ).attr('value')); //alert '2'
13  
14  //Use this if you want to get the label and not the value
15  alert($( "#myselect option:selected" ).text()); //alert 'Mrs'
16</script>

1$( "#myselect option:selected" ).text();
2// => "Mr"
3