Defining the User Agent

Hi there,
I've been trying to do my ACTIONS and they seem very difficult  
without an accurate idea about what we mean by a User Agent; actually  
I think that what it really means is who should conform to UAAG 2.0.  
Anyhow I've been trying to come up with a good all encompassing  
definition - but I can't. So I tried a different approach, a series  
of simple questions (tests) that allow us to define who needs to meet  
our guidelines.

Here's my initial attempt:

If the following three conditions are met then it is a Primary User  
Agent and Must Conform to UAAG:

1) If it is a standalone application; and
2) If it interprets any w3c specified language; and
3) If it provides a user interface or interprets either a procedural  
or declaritive language that may be used to provide a user interface.

If the following two conditions are met then it is a User Agent  
Extension or Plug-In and Must Conform to UAAG:

1) If it is launched by, or extends the functionality of, a Primary  
User Agent; and
2) If post-launch user interaction either becomes part of, or is  
within the bounds of, the Primary User Agent.

If the following three conditions are met then it is a Generated User  
Agent (with inaccessible interface) and Must Conform to UAAG:

1) If the user interface is generated by the interpretation of either  
a procedural or declaritive language; and
2) If this interpretation is by a Primary User Agent, User Agent  
Extension or Plug-In; and
3) If user interaction is not passed to and from the Primary User  
Agent, User Agent Extension or Plug-In, or if user interaction does  
not modify the Document Object Model of its containing document.

So these sound a little convoluted but I'd appreciate your thoughts  
and ideas about this approach to UA definition and UAAG  
applicability; and if we think this is useful, any cases for which  
these rules are disproved.

Cheers
Si.

=======================

Simon Harper
University of Manchester (UK)

Human Centred Web Lab: http://hcw.cs.manchester.ac.uk

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