From: Lennon Day-Reynolds <rcoder@...>
Date: 2004-09-16T01:38:53+09:00
Subject: Re: [OT] Re: web-based progress bar

I've done some DHTML stuff like this, and the smoothest (i.e., least
visible redraw lag to the user) way to do it is with the
XmlHttpRequest object, which most modern browsers (IE,
Mozilla/Firefox, Konqeror, Safari) support for at least GET requests.
Your JS code uses that object to fetch some server-side URL, then grab
the result and use it to dynamically update an onscreen element, like
your progressbar.

If you want something similar, just use an iframe element which points
to the server-side "progress bar" page; you should even just be able
to set the "refresh" meta tag the in header of the HTML the iframe
loads, and have the browser refresh it every second or so. Otherwise,
it's a pretty trivial amount of Javascript to refresh just that
element periodically.

Here's some decent documentation on Apple's developer site about using
the XmlHttpRequest object:
http://developer.apple.com/internet/webcontent/xmlhttpreq.html

And they've got a great tutorial on using iframe elements to do
dynamic updates in browser-based interfaces:
http://developer.apple.com/internet/webcontent/iframe.html

-- 
Lennon
rcoder.net