Adding Javascript to my Iframe

Hey guys,

i am currently trying to modify a map that i customized and embedded from Googyle MyMaps.
I want to add a search bar with an autocomplete function to that map but i cant get them linked somehow.
I already checked Google Developers but there is only an example where the map is added manually via html.

Any clues? :slightly_smiling_face:

Greetings, Dawd