Mulitple row insert into db in codeigniter - ajax

Question

ajax change function execute listByBatch() and show the table with data by batch which is post by ajax. And then I trying to insert table rows by insertAttendance, code below:
Jquery post:
$("#batch-list").change(function(){
/*dropdown post */
$.ajax({
url:"<?php echo base_url(); ?>index.php/attendance/list_ByBatch",
data: {batchid: $(this).val()},
type: "POST",
dataType:'json',
success: function(data){
$("#traineeList").html(data);
$("#subTotal").html("Total: " + $('#traineeList tr').length.toString());
document.getElementById("classHour").defaultValue = "4";
}
});
});
Controller:
public function list_ByBatch() {
$batch = $this->input->post('batchid', TRUE);
$data['trainee']= $this->AttendanceModel->get_traineeList($batch);
if (!empty($data['trainee'])) {
echo form_open('attendance/insertAttendance');
echo"<table class='table table-hover type-list2'id='traineeList'>
<tr class='success'>
<th>Trainee ID</th>
<th>Trainee Name</th>
<th>Present</th>
</tr>";
foreach ($data['trainee'] as $row) {
echo "
<tr><td>" . str_pad($row->TraineeID, 7, "0", STR_PAD_LEFT) . "</td>
<td>" . $row->Name . "</td>
<td><input type='checkbox' name='.$row->TraineeID[]' value='" . $row->TraineeID . "' checked></td>
</tr>";
}
echo"</table>";
echo"
<div class='row'>
<div class='form-group col-sm-2'>
<h5 id='subTotal'></h5>
</div>
<div class='form-group col-sm-6'>
<input type='date' class='form-control' name='attnDate' id='attnDate' placeholder='Attendance Date' required>
</div>
<div class='form-group col-sm-2'>
<input type='number ' class='form-control' name='classHour' id='classHour' placeholder='Class Hour' required>
</div>
<div class='form-group col-sm-2'>
<input type='submit' class='btn btn-default btn-success' name='record' value='Record'>
</div>
</div>";
echo "</form>";
}
}
public function insertAttendance() {
$TID ['TID']= $this->input->post('trainee');
$attnDate = $this->input->post('attnDate');
$classHour = $this->input->post('classHour');
echo '<pre>';
print_r($TID);
if(is_array($TID)){
foreach ($TID as $TID=>$key) {
$query = "INSERT INTO `tbl_attn_temp` (TraineeID, Date, classHour) VALUES ('" . $key . "','" . $attnDate . "','" . $classHour . "')";
$this->db->query($query);
}
}else{
echo "Trainee ID is not array";
}
}
I just trying to insert all rows (TraineeID) shows in table with "attnDate" and 'classHour" by clicking submit button.