$(document).ready(function() {
            $(".users").click(function () {
                $("#user_devices").show();
                var user_id = $(this).attr('user_id');
                $.ajax({
                    url: 'user_devices.php',
                    type: 'GET',
                    data: {user_id: user_id}
                }).done(function (result) {
                    $('#user_devices').html(result);
                });
                $("#user_devices_dropdown").show();
                var device_id = $(this).attr('dropdown_select');
                $.ajax({
                    url: 'select_device.php',
                    type: 'POST',
                    data: {user_id: user_id, device_id: device_id}
                }).done(function (dropdown_result) {
                    $('#user_devices_dropdown').html(dropdown_result);
                    $(".save_device").click(function() {
                        var device_id = $('#dropdown_select: selected').attr('value');
                        $.ajax({
                            url: 'save_user_devices.php',
                            type: 'POST',
                            data: {user_id: user_id, device_id: device_id}
                        }).done(function (save_result) {
                            $("#user_devices_dropdown").html(save_result);
                        });
                    });
                });
            });
        });