jquery if chacge code example

Example 1: on change jquery

$("input").change(function(){
  alert("The text has been changed.");
});

Example 2: click select option to update div jquery

$('#choose').change(function(event) {
        $.post('info.php', { selected: $('#choose').val() },
            function(data) {
                $('#update').html(data);
            }
        );            
    });