dynamically set y axis (position) with javascript

Hello

I wonder if it is possible with javascript to set a y position of flowed subform in non interactive adobe form?

For example: For a certain subform  which is inclued in (flowed) main I want to be shown at certain vertical (y) position but only in the last page at bottom of main.

Last page I can find with

if(xfa.layout.page(this) == xfa.layout.pageCount())

but when changing

this.y = "100 mm"

it doesn't changes subform position.

I also tried with this.y = "100in", but result is the same.

Does anybody now a solution?