Modified "get" action for forms?

[Chris Shaffer]

I have a database search form with many input fields, only a few of which 
are used in the average search.  I'd like the search logic to be embedded 
in the URL so that search results pages can be bookmarks or 
favorites.  However, action="get" puts all the fields in the URL, which 
results in a very long URL.  I'd like to generate a URL that only includes 
non-null input fields.  Is there any way to do this that 1) does not use 
javascript and 2) does not disable the browser back button via redirect?

FYI, our web server is Unix, Apache, PHP, MySQL.
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Chris Shaffer, Technology Coordinator
National Network of Libraries of Medicine, Greater Midwest Region
Library of the Health Sciences, University of Illinois at Chicago
shaffer at uic.edu     http://www.nnlm.nlm.nih.gov/gmr/
312-996-2464 (voice)     312-996-2226 (fax)