Call to undefined method CI_Loader::section() in codeigniter-CodePudding

Currently I'm trying to write an AJAX script under my views folder in codeigniter. for this I have used <?= $this->section('scripts')?> to create a script inside the php file. But doing so gives me Fatal error: Call to undefined method CI_Loader::section(). Here is my full code:

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="utf-8">
    <title>CodeIgniter MVC Basics</title>
</head>
<body>
    <form method='post' action="index">
    <h1>Customer Details</h1>

    <input type="date" name="startDate"/>
    <input type="date" name="endDate"/>
    <select name="status">
        <option>Draft</option>
        <option>Unpublish</option>
        <option>Let</option>
    </select>
    <br/><br/>
    <button type="button" class="alertbox" name="alertbox">alertbox</button>    

    </form>
</body>
</html>

<?= $this->section('scripts')?>

<script>
    $(document).ready(function(){
        $(document).on('click', '.alertbox', function(){
            alert("Hello world");
        });
    });
</script>
<?= $this->endsection()?>

I want it so that whenever the button is clicked, there should be an alert popup in the screen.

EDIT I am loading the view from my controller like this:

$this->load->view('crm/test');

The following is the error:

CodePudding user response：

This code:

$this->load->view('crm/test');

is how you load a view in Codeigniter 3.

This code:

<?= $this->section('scripts')?>
...
<?= $this->endsection()?>

is using layouts, from Codeigniter 4. As shown on that layouts page, and in the main views documentation, to render and display a view in CI 4:

echo view('crm/test');