jquery select option by value

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

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

<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"]')

$('#ddlID').val();
$('#ddlID').text();

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