How to create joomla plugin with jquery code

Question

What is the best way how to add jquery code by Joomla plugin?

How can I set that these code should be applied just for checkout page of VirtueMart in xml file?

Is this the best way?

<?php

// no direct access
defined('_JEXEC') or die;

class plgContentHelloworld extends JPlugin
{
    public function onAfterRender() {
        echo '<script>';
            echo 'alert("Hello World!");';
        echo '</script>';
        }
}

?>

Answer 1

If you are using Joomla 4 you can do it via WebAsset Manager, too: https://docs.joomla.org/J4.x:Web_Assets

JQuery is shipped with Joomla 4. You do not need to add the library yourself; https://docs.joomla.org/Potential_backward_compatibility_issues_in_Joomla_4#jQuery

Answer 2

If you want to use a plugin then you should replace the echo/script you have with code that adds it to the header using the examples here, https://docs.joomla.org/Adding_JavaScript

Or use a 3rd party plugin like Sourcerer from regular labs to do it for you, https://regularlabs.com/sourcerer