How to Create Load content on page scroll using AJAX in CodeIgniter 4

Infinite scroll is a type of pagination where data load automatically while the user scrolling the page.

MySQL database data is loaded using AJAX.

The process will continue until all data is not displayed.

In this tutorial, I show how you can load content on page scroll using jQuery AJAX in CodeIgniter 4.

Demo  Download

1. Database configuration

• Open .env file which is available at the project root.

NOTE – If dot (.) not added at the start then rename the file to .env.

• Remove # from start of database.default.hostname, database.default.database, database.default.username, database.default.password, and database.default.DBDriver.
• Update the configuration and save it.

database.default.hostname = 127.0.0.1
database.default.database = testdb
database.default.username = root
database.default.password = 
database.default.DBDriver = MySQLi

---

2. Enable CSRF

• Again open .env file.
• Remove # from the start of the security.tokenName,security.headerName, security.cookieName, security.expires, security.regenerate, and security.samesite.
• I update the security.tokenName value with 'csrf_hash_name'. With this name read CSRF hash. You can update it with any other value.
• If you don’t want to regenerate CSRF hash after each AJAX request then set security.regenerate = false.

security.tokenName = 'csrf_hash_name' 
security.headerName = 'X-CSRF-TOKEN' 
security.cookieName = 'csrf_cookie_name' 
security.expires = 7200 
security.regenerate = true 
security.redirect = true 
security.samesite = 'Lax'

• Open app/Config/Filters.php file.
• Uncomment 'csrf' in 'before' if commented.

// Always applied before every request
public $globals = [
    'before' => [
       //'honeypot'
       'csrf',
    ],
    'after' => [
       'toolbar',
       //'honeypot'
    ],
];

---

3. Create Table

• Create a new table posts using migration.

php spark migrate:create create_posts_table

• Now, navigate to app/Database/Migrations/ folder from the project root.
• Find a PHP file that ends with create_posts_table and open it.
• Define the table structure in the up() method.
• Using the down() method delete posts table which calls when undoing migration.

<?php namespace App\Database\Migrations;

use CodeIgniter\Database\Migration;

class CreatePostsTable extends Migration
{
    public function up() {
       $this->forge->addField([
             'id' => [
                   'type' => 'INT',
                   'constraint' => 5,
                   'unsigned' => true,
                   'auto_increment' => true,
             ],
             'title' => [
                   'type' => 'VARCHAR',
                   'constraint' => '100',
             ],
             'description' => [
                    'type' => 'TEXT',
                    'null' => true,
             ],
             'link' => [
                    'type' => 'VARCHAR',
                    'constraint' => '255',
             ],
        ]);
        $this->forge->addKey('id', true);
        $this->forge->createTable('posts');
    }

    //--------------------------------------------------------------------

    public function down() {
       $this->forge->dropTable('posts');
    }
}

• Run the migration –

php spark migrate

---

4. Model

• Create Posts Model –

php spark make:model Posts

• Open app/Models/Posts.php file.
• In $allowedFields Array specify field names – ['title','description','link'] that can be set during insert and update.

Completed Code

<?php

namespace App\Models;

use CodeIgniter\Model;

class Posts extends Model
{
     protected $DBGroup = 'default';
     protected $table = 'posts';
     protected $primaryKey = 'id';
     protected $useAutoIncrement = true;
     protected $insertID = 0;
     protected $returnType = 'array';
     protected $useSoftDeletes = false;
     protected $protectFields = true;
     protected $allowedFields = ['title','description','link'];

     // Dates
     protected $useTimestamps = false;
     protected $dateFormat = 'datetime';
     protected $createdField = 'created_at';
     protected $updatedField = 'updated_at';
     protected $deletedField = 'deleted_at';

     // Validation
     protected $validationRules = [];
     protected $validationMessages = [];
     protected $skipValidation = false;
     protected $cleanValidationRules = true;

    // Callbacks
    protected $allowCallbacks = true;
    protected $beforeInsert = [];
    protected $afterInsert = [];
    protected $beforeUpdate = [];
    protected $afterUpdate = [];
    protected $beforeFind = [];
    protected $afterFind = [];
    protected $beforeDelete = [];
    protected $afterDelete = [];
}

---

5. Route

• Open app/Config/Routes.php file.
• Define 2 routes –
  • / – Load initial page content.
  • getPosts – To handle page scroll AJAX request.

Completed Code

$routes->get('/', 'PostsController::index');
$routes->post('getPosts', 'PostsController::getPosts');

---

6. Controller

• Create PostsController Controller –

php spark make:controller PostsController

• Open app/Controllers/PostsController.php file.
• Import Posts Model.
• I defined a class variable –
  • rowperpage – To store the number of records fetch at a time. I set it to 4. Adjust its value according to your requirement.
• Create 2 methods –
  • index() – Assign $this->rowperpage to $data['rowperpage'], total number of record to $data['totalrecords'] and fetch records from posts table.

Load index view and pass $data.

• • getPosts() – This method is use to handle page scroll AJAX requests.

Read POST values and assign to $postData variable. Assign $postData['start'] to $start.

Fetch records from posts table according to $start and $this->rowperpage value. Loop on the fetched records and create HTML layout and assign to $html variable.

Assign new CSRF token hash to $data['token'] and $html to $data['html'].

Return $data Array in JSON format.

Completed Code

<?php

namespace App\Controllers;

use App\Controllers\BaseController;
use App\Models\Posts;

class PostsController extends BaseController {

     public $rowperpage = 4; // Number of rowsperpage

     public function index() {
           $posts = new Posts();

           // Number of rowsperpage
           $data['rowperpage'] = $this->rowperpage;

           // Total number of records
           $data['totalrecords'] = $posts->select('id')->countAllResults();

           // Fetch 4 records
           $data['posts'] = $posts->select('*') 
                                ->findAll($this->rowperpage, 0);

           return view('index',$data);
     }

     public function getPosts(){ 
            $request = service('request'); 
            $postData = $request->getPost(); 
            $start = $postData['start'];

            // Fetch records
            $posts = new Posts();
            $records = $posts->select('*') 
                         ->findAll($this->rowperpage, $start);

            $html = "";
            foreach($records as $record){
                  $id = $record['id'];
                  $title = $record['title'];
                  $description = $record['description'];
                  $link = $record['link'];

                  $html .= '<div class="card w-75 post">
                       <div class="card-body">
                            <h5 class="card-title">'.$title.'</h5>
                            <p class="card-text">'.$description.'</p>
                            <a href="'.$link.'" target="_blank" class="btn btn-primary">Read More</a>
                       </div>
                  </div>';
            }

            // New CSRF token
            $data['token'] = csrf_hash();

            // Fetch data
            $data['html'] = $html;

            return $this->response->setJSON($data);
     }
}

---

7. View

Create index.php file in app/Views/.

I included Bootstrap CSS only for design.

Create a hidden element to store CSRF token name specified in .env file in the name attribute and store CSRF hash in the value attribute.

<input type="hidden" class="txt_csrfname" name="<?= csrf_token() ?>" value="<?= csrf_hash() ?>" />

Loop on $posts and create layout. I added 'post' class on the <div > to find last content while appending new content.

Created 3 hidden fields –

1. Store current row position.
2. Store the number of rows fetch at a time.
3. Store the total number of records.

Script –

Create 2 functions –

• checkWindowSize() – Using this function to check if the screen is too large or the page has not have enough content to scroll. If the condition is true then fetch new records by calling fetchData() function.
• fetchData() – Using this function fetch new records.

Get values from hidden fields and store them in variables. Add rowperpage with start. If start value is <= allcount then update #start value.

Read CSRF token name and hash and assign to variables.

Send AJAX POST request to site_url('getPosts') where pass {[csrfName]: csrfHash,start:start} as data, set dataType: 'json'.

On successful callback append new fetched data response.html after last <div class='post '>. Also, update CSRF token.

Call checkWindowSize() function to again check if the page is scrollable or not.

Define $(window).scroll event, using this check if scroll position reaches end then fetch new records by calling fetchData() function.

Similarly, define touchmove event for mobile, using this check if scroll position reaches end then fetch new records by calling fetchData() function.

Completed Code

<!DOCTYPE html>
<html>
<head>
      <meta charset="utf-8">
      <meta name="viewport" content="width=device-width, initial-scale=1.0">

       <title>Load content on page scroll using AJAX in CodeIgniter 4</title>

       <link rel="stylesheet" type="text/css" href="https://cdn.jsdelivr.net/npm/bootstrap@5.1.0/dist/css/bootstrap.min.css">

       <style type="text/css">
       .card{
           margin: 0 auto;
           margin-top: 35px;
       }
       </style>
</head>
<body>

     <div class='container'>

          <!-- CSRF Token -->
          <input type="hidden" class="txt_csrfname" name="<?= csrf_token() ?>" value="<?= csrf_hash() ?>" />

          <?php 
          foreach($posts as $post){
               $id = $post['id'];
               $title = $post['title'];
               $description = $post['description'];
               $link = $post['link'];
          ?>

               <div class="card w-75 post">
                   <div class="card-body">
                       <h5 class="card-title"><?= $title ?></h5>
                      <p class="card-text"><?= $description ?></p>
                      <a href="<?= $link ?>" target="_blank" class="btn btn-primary">Read More</a>
                   </div>
               </div>
           <?php 
           }
           ?>

           <input type="hidden" id="start" value="0">
           <input type="hidden" id="rowperpage" value="<?= $rowperpage ?>">
           <input type="hidden" id="totalrecords" value="<?= $totalrecords; ?>">

     </div>

     <!-- Script -->
     <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.6.0/jquery.min.js"></script>
     <script type="text/javascript">

     checkWindowSize();

     // Check if the page has enough content or not. If not then fetch records
     function checkWindowSize(){
           if($(window).height() >= $(document).height()){
                // Fetch records
                fetchData();
           }
       }

       // Fetch records
       function fetchData(){
            var start = Number($('#start').val());
            var allcount = Number($('#totalrecords').val());
            var rowperpage = Number($('#rowperpage').val());
            start = start + rowperpage;
 
            if(start <= allcount){
                 $('#start').val(start);

                 // CSRF Hash 
                 var csrfName = $('.txt_csrfname').attr('name'); 
                 // CSRF Token name 
                 var csrfHash = $('.txt_csrfname').val(); // CSRF hash

                 $.ajax({
                      url:"<?=site_url('getPosts')?>",
                      type: 'post',
                      data: {[csrfName]: csrfHash,start:start},
                      dataType: 'json',
                      success: function(response){

                            // Add
                            $(".post:last").after(response.html).show().fadeIn("slow");

                            // Update token
                            $('.txt_csrfname').val(response.token);

                            // Check if the page has enough content or not. If not then fetch records
                            checkWindowSize();
                       }
                  });
            }
       }
       $(document).on('touchmove', onScroll); // for mobile
       function onScroll(){ 

             if($(window).scrollTop() > $(document).height() - $(window).height()-100) {

                    fetchData(); 
             }
        }
       
       $(window).scroll(function(){

              var position = $(window).scrollTop();
              var bottom = $(document).height() - $(window).height();

              if( position == bottom ){
                    fetchData(); 
              }

       });
      
       </script>
</body>
</html>

---

8. Run

• Navigate to the project using Command Prompt if you are on Windows or terminal if you are on Mac or Linux, and
• Execute “php spark serve” command.

php spark serve

• Run http://localhost:8080 in the web browser.

---

9. Demo

View Demo

---

10. Conclusion

You can use it as a replacement of traditional pagination.

New data load while scrolling the page, it works even if there is not limited content for scrolling.

Share this post