Can I output/flush data to screen while processing ajax page?

Question

I need to display on my page a list of records pulled from a table. Ajax works fine (I query the database and put all the data inside a on the main page) but if I have lots of records (say 500+) it will hang until data is fully loaded, THEN it will be sent back to the page and correctly displayed.

I would like to be able to display the records on the page while getting them, instead of being forced to wait until completion. I am trying with flush(); inside the remote (ajax) page but it still waits until full data is loaded.

This is what I currently have inside the ajax page:

At the very beginning:

@apache_setenv('no-gzip', 1);
@ini_set('zlib.output_compression', 0);
@ini_set('implicit_flush', 1);
for ($i = 0; $i < ob_get_level(); $i++) { ob_end_flush(); }
 ob_implicit_flush(1);

Then whenever I have a echo call:

ob_flush();

Now if I load the ajax page alone... it will list the records while reading them from the database. But if I call the same page via Ajax, it will hang and send all the data at once.

Any idea?

This is the function I use to get the ajax content ('id' is the target , 'url' refers to the ajax page that runs the database query to list the records):

function ajax(id,url) {
 xmlhttp=new XMLHttpRequest();
 xmlhttp.open("GET",url,false);
 xmlhttp.send(null);
 document.getElementById(id).innerHTML = parseScript(xmlhttp.responseText);
}