https://www.w3schools.com/ac?on_page.php code example
Example 1: php example
<?php
/* Is called when eio_nop() finished */
function my_nop_cb($data, $result) {
echo "my_nop ", $data, "\n";
}
// This eio_nop() call will be cancelled
$req = eio_nop(EIO_PRI_DEFAULT, "my_nop_cb", "1");
var_dump($req);
eio_cancel($req);
// This time eio_nop() will be processed
eio_nop(EIO_PRI_DEFAULT, "my_nop_cb", "2");
// Process requests
eio_event_loop();
?>
Example 2: php example
sudo yum install php