Question

Is it possible to add items to a select (list box) of html/php through jQuery or javascript when a specific action is triggered by another control in jQuery/javascript? (edited by Alex Thomas)

Answer 1

Yes, attach a suitable handler to the event of your choice. For example if you want to add new items when another control changes, you might use something like this:

$('#controller').change(function() {
    $('#child_select').append('<option>New option</option>');
});

Or alternatively, there are jQuery plugins available to make the drop down list dynamic based on the selection of another element.