Re: HTML is a formatting/UI language

Subject: Re: HTML is a formatting/UI language
From: "Jonathan Borden" <jborden@xxxxxxxxxxxx>
Date: Tue, 20 Apr 1999 11:26:51 -0400
I wanted to expand on my comments last night.

Håkon Wium Lie wrote:
>
> There is a small cost involved in the server-side conversion, yes. But
> you can still do the client side processing since all your data is
> still there.

    HTML and browsers are being asked to expand their role beyond being the
terminal of the 1990's. The browser has become an application platform (this
concept is hardly new). Technologies like 'Dynamic HTML', Java and
Javascript have formed what has been thought of as the browser platform.  I
am suggesting that XML + XSL has alot to add to this equation. Using the
well known MVC (model view controller) paradigm, the model/document is
expressed in XML and the view is expressed in HTML ... the typical case uses
a GUI but HTML is appropriate for non-graphic UI as well, fine, no argument.
For any sort of sophisticated program design it remains helpful to have a
separate document layer. XSL is a terrific way to link the XML
document/model layer with the HTML view layer. As such, essentially any UI
which can be created in something like VB can also be created using the
browser platform and standards.
    There is a common misconception that environments like VB have the
ability to create a more sophisticated UI for 'in-house' applications. This
is untrue if we use sophisticated and standard tools such as XSL and
JavaScript. If Java is also tightly integrated into the browser environment
e.g. XPConnect, it will also play in this environment.
    In this architecture, The browser is the client and XML is the 'RPC'
wire format for distributed web applications. The distributed object call
e.g. CORBA or DCOM becomes:

    client-> HTTP request PDU = MIME message with Content-Type: text/xml or
application/xml

    server does something with the XML request and returns:

    HTTP response PDU = MIME message with Content-Type: text/xml or
application/xml

    As someone who has been doing distributed objects for years, I see the
tradeoff as being a few extra bytes of wire representation (XML is lengthier
than a binary format) versus the ease of passing messages across firewalls
etc. What I am taking about is not necessarily a better way to write HTML
pages or distribute HTML content rather a better way to write distributed
applications (those applications which until now are typically written using
distributed object technologies).

    To the extent that the logic of client side processing can be expressed
as a set of transformations, XSL is a declarative language which interfaces
with the user interface layer via generation of HTML.

Jonathan Borden
http://jabr.ne.mediaone.net




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