problems of Drop Down boxes with history back

[gary]

In our site we are encountering problems with drop down boxes.
we have a dropdown box & the ONChange event of which is fetching some
data from a servlet. However when we use history back button , the data
of previous page is displayed correctly but the dropdown selected index
always lags behind by one.
Fo instance if the selected index of dropdown is 1 data relating to it
is diplayed on table, if second option is selected a call to servlet
returns data relating to the second selection in the table et-al.
However if we click back it correctly shows the cached data of previous
dropdown value but the item in the drop down box is still pointing to
the latest one.
Would appreciate solution sharing .
Thanks