Ajax events onchange for double select

Hi,
So I have this application with 1 select and 2 double selects. Each has options from automatic lookups. I want to add Ajax event onChange on select1, so when it’s changed, the values selected on doubleSelect1 and doubleSelect2 changed accordingly.
Note that I need only the selected values that changed, not the original options. So I can’t use ajax processing event onchange in select1.

I originally put the function to fill doubleSelect1 and doubleSelect2 in onLoad events, and checked the option “Reload form when value has changed” in select1. And it works.

The problem is, I use tabs for each field, and whenever the form reloads, the focus will be back to the first tab. I need it so the form doesn’t reload, and the tab focus stays where we choose last.

Can I use the function to fill the doubleSelect fields in ajax event onchange? Or is there any workaround so I don’t have to reload the form when the select1 changed?

Thanks in advance!

Ps. : those three fields are manually made, not automatically from table

Akax processing is not returning selected valuse?

No. I just made 2 new forms.
One of them got the shown select fields automatically from table.
I add ajax processing in one of the field, no problem.
The other one, I added the 2 select fields manually, with the same lookup query, the ajax is not working.

Did I miss some step for manually added field or something?