Parameters set by user

Hopefully I can articulate my earlier question in a more precise way: 

I was trying to find information on how to pass a parameter from the HTML
page down to the XSL, do invoke portions of the stylesheet. From what
results to me, this depends on the transforming machine used. I found
information on how to pass parameter values to XALAN via the command line.
How would this be done instead from an HTML page when using Cocoon?

Matthias

 XSL-List info and archive:  http://www.mulberrytech.com/xsl/xsl-list