Send form data on input change

I am trying to make use of the form-ajax-submit-onchange, everything works pretty well, but it sends the ajaxs request on page init twice! without changing any input.

My guess is that because i am using picker for birthdate and smart select for languages which apearently update the input after the page init. it fires 2 request when ever the page is loaded.

my question if someone has an idea on how i could prevent this from happening?
Basicly i can live with it but i dont think that it would be greate to alaways have 2 extra requests ( minimizing server load)

how about preventdefault , cant help ?