PHP: Flushes the system write buffers phptuts April 24, 2022 We use function flush — Flush system output buffer <?php if (ob_get_level() == 0) ob_start(); for ($i = 1; $i<=10; $i++){ echo "<br> Line $i."; ob_flush(); flush(); sleep(2); } echo "Done."; ob_end_flush(); ?> phptuts