This is how my HTML looks like:

            <div class="row">
                <div class="col-xs-12">

                    <div class="box">
                        <div class="box-header">
                            <h3 class="box-title">Data Table With Full Features</h3>
                        </div>
                        <!-- /.box-header -->
                        <div class="box-body">
                            <table id="example1" class="table table-bordered table-striped">
                                <thead>
                                <tr class="row">
                                    <th>ID</th>
                                    <th>Nome</th>
                                    <th>Cognome</th>
                                    <th>Indirizzo</th>
                                    <th>Email</th>
                                    <th>Tipo contatto</th>
                                    <th>Telefono 1</th>
                                    <th>Telefono 2</th>
                                    <th>Telefono 3</th>
                                    <th>Azioni</th>
                                </tr>
                                </thead>
                                <tbody id="tab-0">

                                </tbody>
                            </table>
                        </div>
                        <!-- /.box-body -->
                    </div>
                    <!-- /.box -->
                </div>
                <!-- /.col -->
            </div>
            <!-- /.row -->

And this is how the JSON data in composed in PHP

        if ($result = $this->hookUp->query($this->sqlA)) {
            while ($row = mysqli_fetch_array($result, MYSQLI_BOTH)) {

                $id = $row['id'];

                $data[] = array("id" => "<td>" . $row['id'] . "</td>",
                    "nome" => "<td id='nome:" . $id . "' contenteditable='true'>" . $row['nome'] . "</td>",
                    "cognome" => "<td id='cognome:" . $id . "' contenteditable='true'>" . $row['cognome'] . "</td>",
                    "indirizzo" => "<td id='indirizzo:" . $id . "' contenteditable='true'>" . $row['indirizzo'] . "</td>",
                    "email" => "<td id='email:" . $id . "' contenteditable='true'>" . $row['email'] . "</td>",
                    "tipo_contatto" => "<td id='tipo_contatto:" . $id . "' contenteditable='true'>" . $row['tipo_contatto'] . "</td>",
                    "telefono_1" => "<td id='telefono_1:" . $id . "' contenteditable='true'>" . $row['telefono_1'] . "</td>",
                    "telefono_2" => "<td id='telefono_2:" . $id . "' contenteditable='true'>" . $row['telefono_2'] . "</td>",
                    "telefono_3" => "<td id='telefono_3:" . $id . "' contenteditable='true'>" . $row['telefono_3'] . "</td>",
                    "edit" => "<td>" . '<a id="' . $row['id'] . '" class="delete" href="#"><i class="fa fa-fw fa-remove"></i></a>
                    <a id="' . $row['id'] . '" class="edit" href="#"><i class="fa fa-fw fa-edit"></i>' . "</a></td>");

                $response['cliente'] = $data;

                $fp = fopen("../lista.json", "w");
                fwrite($fp, json_encode($response));
                fclose($fp);
            }
        }

This is how the JSON data is appended:

        $.getJSON("lista.json", function (json) {

            if (json.cliente) {

                for (i = 0; i < json.cliente.length; i++) {
                    var obj = json.cliente[i];

                    var output = "<tr class='row'>";

                    for (var key in obj) {
                        name = key;
                        value = obj[key].toString();

                        output += value;
                    }

                    output += "</tr>";

                    console.log(output);

                    $("#tab-0").append(output);
                }

            }

[...] close brackets.