does not support populating values via ajax?

[softnayr]

I tried this code which gets data returned from ajax but it does not work:

$("#category_id option").remove(); // Remove all child tags.
$.each(data.message, function(index, item) {
$("#category_id").append($(item) );
});

[gyduxa]

The code below worked for me.

On change of one selectbox, the second gets populated.
The php file must contain the options of the second selectbox from the selected value of the first selectbox.

$('select.lvl1').selectBox().change(function () {
    $.ajax({
        method: "POST",
        url: 'populate.php',
        data: { cat: $('select.lvl1').val() },
        dataType: 'html'
    }).done(function(data) {
        $('select.lvl2').selectBox().setOptions(data);
    });
});