Hæ?

When I was a child we were taught at home
to ask : ¨Hva sa du?¨ (What did you say?)
and preferably not only ¨Hva?¨ (What?).
What we were certainly not to ask was ¨Hæ?¨
This word for What? was considered vulgar in my
family.

Now I hear it so often among young and old people
talking to each other here in Moss.
I wonder if it is to be considered a dialect word
in this region or perhaps a slang word that
keeps alive, decade after decade.

Hæ?