Re: RPG and AJAX was->RE: How do I create a web pagethat....

>Now, he MIGHT have wanted line by line validation, but he didn't specify
it, and yet the immediate answer from some people was to add server-side
validation via AJAX, without a thought to performance or complexity.

Good point.  Let's dig in deeper.

First off. Learn AJAX. What it is, what it does, go through a basic example.

http://en.wikipedia.org/wiki/Ajax_%28programming%29


With your basic example in place go ahead and do some performance testing by
hitting it with a client side application. I have developed my own little
thick client java app where I put in a URL, the content to POST, which
headers to send, and how many times to call it iteratively. Note that this
is "get a rough idea" performance testing.  Obviously doing it this way it
is being limited by the number of synchronous connections I am making to the
AJAX enabled application.

Next, find a good framework. No sense in recreating the wheel. Here are a
couple:
http://dojotoolkit.org/
http://www.modernmethod.com/sajax/


Depending on the language you plan on using you may want to adopt an
existing technology (i.e. Tapestry) which has open source AJAX support
through tacos.sourceforge.net.

Is that better Joe ;-)

Aaron Bartell


-----Original Message-----
From: web400-bounces@xxxxxxxxxxxx [mailto:web400-bounces@xxxxxxxxxxxx] On
Behalf Of Joe Pluta
Sent: Wednesday, April 05, 2006 1:39 PM
To: 'Web Enabling the AS400 / iSeries'
Subject: Re: [WEB400] RPG and AJAX was->RE: How do I create a web
pagethat....

AJAX will be the most overused technology for the next 6-12 months, until
people realize that it's just not necessary for the majority of
applications.  In Charles' case, his initial request was to be able to enter
items and have them appear on the bottom of the page as he enters each one.
He didn't say anything about validating the entries, simply keeping track of
them using a single input field.  This could be done with a very simple fewe
lines of JavaScript.

Now, he MIGHT have wanted line by llne validation, but he didn't specify it,
and yet the immediate answer from some people was to add server-side
validation via AJAX, without a thought to performance or complexity.

When you start changing from one web hit for a page to one web hit for every
field, you're going to find that issues like latency start to become much
more pronounced.  It's perhaps less of a problem with an Intranet
application, but if this application is ever meant to go out to slower speed
connections, then AJAX may not be the idea.

I'm not against AJAX by any means.  There are applications where it makes
sense.  The problem is that there are a LOT of issues that need to be dealt
with, especially when it comes to opening up multiple persistent connections
to the host. (Oh ho, you say... we don't NEED persistence!  Well, if you're
planning on using any of the capabilities of i5/OS, like library lists and
security, then you will need persistence of some kind.)

Anyway, my two cents.  AJAX is a cool technology, but it's not the universal
panacea, and it's very "coolness" makes it highly susceptible to overuse.

Joe


> From: albartell
> 
> >Any recommendations on where to start?
> 
> If you can wait until the end of the month I have an article coming 
> out in the May issue of iSeries News titled "RPG and Ajax: Together At
Last"
> 
> It will guide you through the bare bones of AJAX and RPG.  The example 
> used in the article is validating an item number and changing the 
> appearance of the page based on the item entered being valid or 
> invalid.


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