on select option jquery code example

Example 1: select option value jquery

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

Example 2: jquery select option by value

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

Example 3: dropdown option selection change event in jquery

$("select [name='element_name']").change(function(){
	// condition goes here
});