HTML variable question

[Brent Wood]

gidday,

I have a mapfile picking up a parameter from the html from a select list, to
choose a value in an Postgis SQL to restrict the returned values. If I zoom,
however, I lose the value. 

Is there any way to pass an html variable to the html template to "remember"
the selected member in the select list (without having to resort to mapscript)?

ie: HTML select returns trip=tan0601

mapfile data statement has:

select the_geom from (select * from stations where trip="%trip%") as myquery
using unique oid using SRID=4326 


This works perfectly, and displays just the selected data but when I zoom, 
the selection is lost. Is there any way I can set up the mapfile & html
template to retain the selected value?


Thanks,

  Brent Wood