PHP实时输出时出错

Question

header( 'Content-type: text/html; charset=utf-8' );
echo 'Begin ...<br />';
ob_start();
for( $i = 0 ; $i < 10 ; $i++ )
{
    echo $i . '<br />';
    flush();
    ob_flush();
    sleep(1);
}

why these code is not output $i each second? it output on 10 second later

Answer 1

It seems to me that your code is, indeed, outputing $i in every 1 second steadily when ran from the terminal but it doesn't do it when load through web.

The workaround for you is to enable implicit flushing: http://php.net/manual/en/function.ob-implicit-flush.php

And remove that ob_start() call. The following code works perfectly:

<?php
    header( 'Content-type: text/html; charset=utf-8' );
    echo 'Begin ...<br />';
    ob_implicit_flush (1);
    for( $i = 0 ; $i < 10 ; $i++ )
    {
        echo $i . '<br />';
        flush();
        ob_flush();
        sleep(1);
    }
?>