JSP Dynamic content problem

Question

In my jsp page I have 2 combo boxes--data of 2nd comboBox is dependent on the 1st. The data for both is previously obtained from a database. How to do this ? I'm using MVC 1 archi.

Answer 1

You have 2 options
1. Populate the 1st combo-box. In the onChange event, submit a
request to the server. In the server, get the value of the 1st combo that
would be passed in the request and then get the corresponding 2nd
combo box values from the db and repopulate the original form with the
values.
Pros : Neat, all data manipulation at the backend.
Cons : Round trip to the server.
Usage: Use only if this page wouldnt be requested ordinarily and you
are sure that the number of changes in the combo1 by any user would
be limited.
2. Load the combo1 and combo2 values (& the relation between them)
all on first shot. Use javascript to lookup the values of the 2nd combo
based on the selection in the 1st.
Pros : No Round trips to the server each time on value change. Quite
fast
Cons : javascipt. This can get very very messy, you require extensive
cross browser testing; maintenance is another issue.
Usage: Consider this if this page will have large number of hits in your
ui flow.Have a javascript guru around, document the code extensively .
cheers,
ram.