AutoPostBack clears calculated results

I have a number of Div’s on a form
In each Div there are a number of asp.dropdownlist’s – with the datasource of an Access Database.  Some of them with autopostback (this is nessessary to populate the DDL’s).
This all works fine
In  each Div the is a Text Box (named Div1TextBox, Div2TextBox Div3TextBox, etc)
On the Form (in the header) there is some Javascript that takes the value of 1 DDL and multiplies it by the value of another and places the result in the text box
This “almost” works.  Each Div calculation works.
BUT when I do the calculation in the next div – the autopostback removes the results in all the other Divs.

How can I allow the autopostback to run BEFORE the Javascript AND maintain the values of other calculated results?

Thanks

J