JQuery: 'Uncaught TypeError: Illegal invocation' at ajax request - several elements

Question

I have two select elements, A and B: when A\'s selected option changes, B\'s options must be updated accordingly. Each element in A implies many elements in B, it\'s a one-t

Answer 1

I've read in JQuery docs that data can be an array (key value pairs). I get the error if I put:

This is object not an array:

var data = {
        'mode': 'filter_city',
        'id_A': e[e.selectedIndex]
};

You probably want:

var data = [{
        'mode': 'filter_city',
        'id_A': e[e.selectedIndex]
}];