<div>Records Per Page: <select name="per_page" onchange="setPerPage()">
<option value="3" selected>100</option>
<option value="0">10</option>
<option value="1">20</option>
<option value="2">50</option>
</select></div>

function setPerPage() {
var perPageSelector = document.querySelector('#results-tbl select');
var lastSegment = window.location.pathname.split('/').pop();
var selectedIndex = perPageSelector.value;
var targetUrl = window.location.protocol + '//' + window.location.hostname + window.location.pathname;
targetUrl = targetUrl.replace('/manage/', '/set_per_page/' + selectedIndex + '/');
targetUrl = targetUrl.replace('/manage', '/set_per_page/' + selectedIndex + '/');
window.location.href = targetUrl;
}

<h1><?= $headline ?></h1>
<?php
flashdata();
echo '<p>'.anchor('page_tests/create', 'Create New Page Test Record', array("class" => "button")).'</p>';
echo Pagination::display($pagination_data);
if (count($rows)>0) { ?>
<table id="results-tbl">
<thead>
<tr>
<th colspan="4">
<div>
<div><?php
echo form_open('page_tests/manage/1/', array("method" => "get"));
echo form_input('searchphrase', '', array("placeholder" => "Search records..."));
echo form_submit('submit', 'Search', array("class" => "alt"));
echo form_close();
?></div>
<div>Records Per Page: <?php
$dropdown_attr['onchange'] = 'setPerPage()';
echo form_dropdown('per_page', $per_page_options, $selected_per_page, $dropdown_attr);
?></div>

</div>
</th>
</tr>
<tr>
<th>Last Name</th>
<th>First Name</th>
<th>Company Name</th>
<th style="width: 20px;">Action</th>
</tr>
</thead>
<tbody>
<?php
$attr['class'] = 'button alt';
foreach($rows as $row) { ?>
<tr>
<td><?= $row->last_name ?></td>
<td><?= $row->first_name ?></td>
<td><?= $row->company_name ?></td>
<td><?= anchor('page_tests/show/'.$row->id, 'View', $attr) ?></td>
</tr>
<?php
}
?>
</tbody>
</table>
<?php
if(count($rows)>9) {
unset($pagination_data['include_showing_statement']);
echo Pagination::display($pagination_data);
}
}
?>

<?php
class Page_tests extends Trongate {

private $default_limit = 20;
private $per_page_options = array(10, 20, 50, 100);

function create() {
$this->module('trongate_security');
$this->trongate_security->_make_sure_allowed();

$update_id = segment(3);
$submit = post('submit');

if (($submit == '') && (is_numeric($update_id))) {
$data = $this->_get_data_from_db($update_id);
} else {
$data = $this->_get_data_from_post();
}

if (is_numeric($update_id)) {
$data['headline'] = 'Update Page Test Record';
$data['cancel_url'] = BASE_URL.'page_tests/show/'.$update_id;
} else {
$data['headline'] = 'Create New Page Test Record';
$data['cancel_url'] = BASE_URL.'page_tests/manage';
}

$data['form_location'] = BASE_URL.'page_tests/submit/'.$update_id;
$data['view_file'] = 'create';
$this->template('admin', $data);
}

function manage() {
$this->module('trongate_security');
$this->trongate_security->_make_sure_allowed();

if (segment(4) !== '') {
$data['headline'] = 'Search Results';
$searchphrase = trim($_GET['searchphrase']);
$params['last_name'] = '%'.$searchphrase.'%';
$params['first_name'] = '%'.$searchphrase.'%';
$params['company_name'] = '%'.$searchphrase.'%';
$sql = 'select * from page_tests
WHERE last_name LIKE :last_name
OR first_name LIKE :first_name
OR company_name LIKE :company_name
ORDER BY id';
$all_rows = $this->model->query_bind($sql, $params, 'object');
} else {
$data['headline'] = 'Manage Page Tests';
$all_rows = $this->model->get('id');
}

$pagination_data['total_rows'] = count($all_rows);
$pagination_data['page_num_segment'] = 3;
$pagination_data['limit'] = $this->_get_limit();
$pagination_data['pagination_root'] = 'page_tests/manage';
$pagination_data['record_name_plural'] = 'page tests';
$pagination_data['include_showing_statement'] = true;
$data['pagination_data'] = $pagination_data;

$data['rows'] = $this->_reduce_rows($all_rows);
$data['selected_per_page'] = $this->_get_selected_per_page();
$data['per_page_options'] = $this->per_page_options;
$data['view_module'] = 'page_tests';
$data['view_file'] = 'manage';
$this->template('admin', $data);
}

function show() {
$this->module('trongate_security');
$token = $this->trongate_security->_make_sure_allowed();
$update_id = segment(3);

if ((!is_numeric($update_id)) && ($update_id != '')) {
redirect('page_tests/manage');
}

$data = $this->_get_data_from_db($update_id);
$data['token'] = $token;

if ($data == false) {
redirect('page_tests/manage');
} else {
$data['update_id'] = $update_id;
$data['headline'] = 'Page Test Information';
$data['view_file'] = 'show';
$this->template('admin', $data);
}
}

function _reduce_rows($all_rows) {
$rows = [];
$start_index = $this->_get_offset();
$limit = $this->_get_limit();
$end_index = $start_index + $limit;

$count = -1;
foreach ($all_rows as $row) {
$count++;
if (($count>=$start_index) && ($count<$end_index)) {
$rows[] = $row;
}
}

return $rows;
}

function submit() {
$this->module('trongate_security');
$this->trongate_security->_make_sure_allowed();

$submit = post('submit', true);

if ($submit == 'Submit') {

$this->validation_helper->set_rules('last_name', 'Last Name', 'required|min_length[2]|max_length[255]');
$this->validation_helper->set_rules('first_name', 'First Name', 'required|min_length[2]|max_length[255]');
$this->validation_helper->set_rules('company_name', 'Company Name', 'required|min_length[2]|max_length[255]');

$result = $this->validation_helper->run();

if ($result == true) {

$update_id = segment(3);
$data = $this->_get_data_from_post();

if (is_numeric($update_id)) {
//update an existing record
$this->model->update($update_id, $data, 'page_tests');
$flash_msg = 'The record was successfully updated';
} else {
//insert the new record
$update_id = $this->model->insert($data, 'page_tests');
$flash_msg = 'The record was successfully created';
}

set_flashdata($flash_msg);
redirect('page_tests/show/'.$update_id);

} else {
//form submission error
$this->create();
}

}

}

function submit_delete() {
$this->module('trongate_security');
$this->trongate_security->_make_sure_allowed();

$submit = post('submit');
$params['update_id'] = segment(3);

if (($submit == 'Yes - Delete Now') && (is_numeric($params['update_id']))) {
//delete all of the comments associated with this record
$sql = 'delete from trongate_comments where target_table = :module and update_id = :update_id';
$params['module'] = 'page_tests';
$this->model->query_bind($sql, $params);

//delete the record
$this->model->delete($params['update_id'], 'page_tests');

//set the flashdata
$flash_msg = 'The record was successfully deleted';
set_flashdata($flash_msg);

//redirect to the manage page
redirect('page_tests/manage');
}
}

function _get_limit() {
if (isset($_SESSION['selected_per_page'])) {
$limit = $this->per_page_options[$_SESSION['selected_per_page']];
} else {
$limit = $this->default_limit;
}

return $limit;
}

function _get_offset() {
$page_num = segment(3);

if (!is_numeric($page_num)) {
$page_num = 0;
}

if ($page_num>1) {
$offset = ($page_num-1)*$this->_get_limit();
} else {
$offset = 0;
}

return $offset;
}

function _get_selected_per_page() {
if (!isset($_SESSION['selected_per_page'])) {
$selected_per_page = $this->per_page_options[1];
} else {
$selected_per_page = $_SESSION['selected_per_page'];
}

return $selected_per_page;
}

function set_per_page($selected_index) {
$this->module('trongate_security');
$this->trongate_security->_make_sure_allowed();

if (!is_numeric($selected_index)) {
$selected_index = $this->per_page_options[1];
}

$_SESSION['selected_per_page'] = $selected_index;
redirect('page_tests/manage');
}

function _get_data_from_db($update_id) {
$record_obj = $this->model->get_where($update_id, 'page_tests');

if ($record_obj == false) {
$this->template('error_404');
die();
} else {
$data = (array) $record_obj;
return $data;
}
}

function _get_data_from_post() {
$data['last_name'] = post('last_name', true);
$data['first_name'] = post('first_name', true);
$data['company_name'] = post('company_name', true);
return $data;
}

}