display string example :- "ASD ZXC 4*8" as "AZ48" in text box

display string example :- "ASD ZXC 4*8" as "AZ48" in text box

I want display string example as:- "ASD ZXC 4*8" as "AZ48" in text box by
java script, How i can do this?
Actually i will enter "ASD ZXC 4*8" in text box then in other text box
"AZ48" will be populate.