Reset select value to default

Answer 1

You can do this way:

var preval = $('#my_select').val(); // get the def value

$("#reset").on("click", function () {
   $('#my_select option[value*="' + preval + '"]').prop('selected', true);
});

checkout this fiddle

take a var which holds the default loaded value before change event then get the option with the attribute selector of value with holds the var value set the property to selected.