iframe used for long polling makes browser show it's still loading

iframe used for long polling makes browser show it's still loading

I tried to use iFrame for long polling. It works fine actually. The
problem is that the indicator of e.g. Chrome says that the page is still
loading? Is there any way to suppress this?
Actually I want to do a simple messaging system. And provide a HTML5
solution with a iFrame fallback if text/event-stream events can't be
fired.
My serverside php looks like:
<?php
header("Content-Type: text/event-stream\n\n");
$i = 0;
while ( $i < 1 ) {
echo "hi";
echo "\n\n";
ob_flush();
flush();
sleep( rand(2, 7) );
}
?>
Do u have any idea how to solve this?
Greetings