Script need to change trim size and margin

I want a script which should change the listed document size with margin ( 0.25") in all sides, If anyone have idea please provide

Document size list

1. Full ( 9" x 10.5" )
2. Half ( 9" x 5.25")
3. Spread ( 18" x 10.5")
4. Tab ( 9.25" x 10.5" )
5. Custom size