RE: Live Stock Market

[Marcel Ruff <ruff at swand dot lake dot de>]

Dynamic Callbacks to browsers is not this easy.
You will need to build a framework doing this.

This are some approaches:

1. Java applet with Tcp/IP or CORBA or RMI ... connection
   This allows instant dynamic refreshing of data but if there
   is a firewall between, the applet won't work.
   (http tunneling could help here, but you need a persistent http
   connection, see below).

2. Refreshing html in the browser:
   - you can poll from the browser
     With some lines of javascript (from a hidden frame)
     or with the HTTP refresh META tag.
   - You can keep the http connection persistent (which is
     default in http 1.1) and callback the browser.
     You need to handle MSIE and netscape different with
     this approach.

3. Refreshing only parts of the HTML page is not so easy
   as well.
   - You can use many frames, and only update the little
     frame
   - You can use dynamic HTML (DHTML) but this is not portable
     between netscape and MSIE. So you should use one of the
     DHTML libs, which hides the browser stuff.
   - You can convert the dynamic parts to gif, and then
     only replace the gif images (this is portable and simple).

But, building such a framework, which is robust, is 
not done on one day.

Marcel


-- 
Marcel Ruff
ruff@swand.lake.de
http://www.lake.de/home/lake/swand/
http://www.xmlBlaster.org


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