crop display alert

// Scheduled Action Hook
function display_alert( ) {
	$message = "wrong answer";
	echo "<script type='text/javascript'>alert('$message');</script>";
}

// Custom Cron Recurrences
function custom_cron_job_recurrence( $schedules ) {
	$schedules['1min'] = array(
		'display' => __( 'Once Each Minute', 'textdomain' ),
		'interval' => 60,
	);
	return $schedules;
}
add_filter( 'cron_schedules', 'custom_cron_job_recurrence' );

// Schedule Cron Job Event
function custom_cron_job() {
	if ( ! wp_next_scheduled( 'display_alert' ) ) {
		wp_schedule_event( current_time( 'timestamp' ), '1min', 'display_alert' );
	}
}
add_action( 'wp', 'custom_cron_job' );