Question

set_time_limit(0);

header("Cache-Control: no-cache, must-revalidate");
header("Expires: Mon, 26 Jul 1997 05:00:00 GMT");
flush();

while($i < 10)
{
    sleep(1);
    $i++;
    echo $i;
    flush();
}

Why doesn’t my code print out 1, then wait and print 2 then wait and print 3. Instead, it just waits 10 seconds and prints out 12345678910 all at once?

Is there a way to print it in chunks as I want?

Answer 1

It’s likely because of output buffering. Try adding this at the top of the file to close all the open buffers:

while(ob_get_level() > 0) {
    ob_end_flush();
}

You can also add ob_flush() after the flush() command in your code:

$i++;
echo $i;
flush();
ob_flush();

(Note that you should only have to do one of them, not both, but try it)…