[xsl] HTTP server-side check

["Schimon Jehudah sch@xxxxxxxxxxxx" <xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx>]

Ladies and Getlemen. Good evening.


I am specifying a what-is-called "middleware" to check two concerns of
client request.

1) Whether XSLT is available.

2) Whether ECMAScript (i.e. JS) is available.

I wrote about this concern, a month ago or so; and, now, I intend to
implement it.


Possibilities
-------------

* If XSLT is detected, then XML document be loaded.

* If XSLT is not detected, and JS is detected; then, the server would
  redirect to a page with a frame with module XSLTProcessor (or
  SaxonJS, or xslt-processor) to process the XML document.

* If neither is detected; then, the server would redirect to a raw
  (X)HTML page be loaded.


Technicalities
--------------

* XSLT be checked by an image (e.g. an invisible pixel).

* JS be checked by "XML HTTP Request".

I ask for your advisories, as to the proper logic to implement this.

If you have other comments or criticism about any of the
technicalities; then, please, write.


Thank you,
Schimon