Question

If I have the next algorithm in the file test.php:

for ($i = 0; $i < 1000; ++$i)
{
     //Operations...
     ALERT_TO_MAIN_PAGE($i);
}

I call test.php with AJAX form the page main.html

How can I track the progress of $i, with live values?

So main.html will show like this, very time the PHP file has completed one iteration:

Done 0.
Done 1.
Done 2.
...

Answer 1

You can try using HTML5 Server Sent Events to send messages like that to the browser.

Right off the website:

<?php
header('Content-Type: text/event-stream');
header('Cache-Control: no-cache'); // recommended to prevent caching of event data.

/**
 * Constructs the SSE data format and flushes that data to the client.
 *
 * @param string $id Timestamp/id of this connection.
 * @param string $msg Line of text that should be transmitted.
 */
function sendMsg($id, $msg) {
  echo "id: $id" . PHP_EOL;
  echo "data: $msg" . PHP_EOL;
  echo PHP_EOL;
  ob_flush();
  flush();
}

$serverTime = time();

sendMsg($serverTime, 'server time: ' . date("h:i:s", time()));