Timeout or other time counters for "For Loop"

[GoogleCodeExporter]

Hello,
This is my code:

GDownloadUrl("proxy.php", function(data) {

var xml = GXml.parse(data);
var markers = xml.documentElement.getElementsByTagName("earhquake");
for (var i=0; i <= markers.length; i++) {
var name = markers[i].getAttribute("name");
var lokasyon = markers[i].getAttribute("lokasyon");
var mag = markers[i].getAttribute("mag");
var Depth = markers[i].getAttribute("Depth");
var latlng = new GLatLng(parseFloat(markers[i].getAttribute("lat")),
                                        parseFloat(markers[i].getAttribute("lng")));
var marker = createMarker(latlng, name, lokasyon, mag, Depth);  
map.addOverlay(marker);

In here, i need:

Insert the first row of XML and stop 5 seconds,
then insert the second row of XML and stop 5 seconds again,
and again, and again...

I have tried some codes like, settimeout(map.addOverlay(marker),5000); but the 
codes didn't work or get the first data only.

So how can i run the "for loop" with some time intervals?
how can i insert the data after 5 seconds?

Sorry for my bad English.
Thanks a lot :)

Original issue reported on code.google.com by cengizha...@gmail.com on 6 Dec 2011 at 9:31