Show output of program in realtime on website

Hi, the program "main" produces x times an output with an delay of 1 second between each output. I want to show this output in "realtime" on a website (this should become a progress-bar). The following code shows the output a f t e r the program ends: CODE... $fp = popen ("./main", "r"); // execute the program while( $zeile=fgets($fp,100) ) { // read and show output echo $zeile; flush(); // ?realtime? } pclose($fp); // close pointer ...CODE Does anybody know how to realise this? Greetings Stefan PS: Linux, PHP4