PHP loop; how to print each result and delay it for a second before echoing another result?

Question

this is my first question here on stackoverflow, I just curious.. is it possible to delay loop in PHP ? I'm trying to print each result to browser and pause the script using sleep() before it process another loop, but it's not working, here's the script that I use:

<?php
$n = 1;

while ($n < 10) {
    echo $n."<br />";
    $n++;
    sleep(1);
}
?>

PS: I'm using Firefox and Apache2 on Linux Mint.

Answer 1

Servers usually buffer the output of a server side script until there's enough in it to output try something like this. Combination of setting output buffering off and manually flushing the buffer. Note the implcit flush line and the flush and ob_flush lines.

<?php 
@ini_set("output_buffering", "Off");
@ini_set('implicit_flush', 1);
@ini_set('zlib.output_compression', 0);
@ini_set('max_execution_time',1200);


header( 'Content-type: text/html; charset=utf-8' );


echo "Testing time out in seconds\n";
for ($i = 0; $i < 1150; $i++) {
    echo $i." -- ";

    if(sleep(1)!=0)
    {
        echo "sleep failed script terminating"; 
        break;
    }
    flush();
    ob_flush();
}

?>

Answer 2

PHP executes and renders its output completely before the page renders its content. So no, you can't delay the PHP loop like you want.

You could and should do this with javascript. If you need information from the server printed on delay like this, you can use AJAX to pull the information from the server as it becomes available.