Rails spinoffs - Aug 2006 - Dynamically update an Ajax.Autocompleter target URL

Hello,

To perform an autocompletion request on my form I have to submit an 
additional parameter (that can be changed by the user)
to the servlet that will handle the user data.
Each time the user changes the parameter''s value (through an html
select
item) a javascript function
rebuilds the autocompletion url (and adds the new value in the 
querystring) and updates the "url" property of my Ajax.Autocompleter 
component but this don''t seems to work.

As a workaround I added the following code to my page:
function rebuildURL(event){
    mycompleter.onObserverEvent=function{}
    mycompleter=new Ajax.Autocompleter(.....)
}

Any ideas on how I can do this more "properly" ??

Thanks

Fred