Cron task plugin ( event schedule when plugin active and unschedule when decactive [ use WP Crontrol to see scheduled event ] )

my-corn.php

<?php
/*
Plugin Name: My WP-Cron Test
*/


//activation of job
register_activation_hook(__FILE__, 'my_activation');

add_action('hourly_job', 'do_hourly_job');

function do_hourly_job() {



	?>

    <script>
        alert();
    </script>

	<?php
}


function my_activation() {
	if (! wp_next_scheduled ( 'hourly_job' )) {

	$result	= wp_schedule_event(time(), 'hourly', 'hourly_job');
     //var_dump( $result );


     }
}


//deactivation job
register_deactivation_hook( __FILE__, 'bl_deactivate' );

function bl_deactivate() {
	$timestamp = wp_next_scheduled( 'hourly_job' );
    $result= wp_unschedule_event( $timestamp, 'hourly_job' );
   // var_dump( $result , $timestamp );
}