Instruction: Extract information from the supporting document to answer the given question.

Input:
Question: Could this work on the arm of a chair or sofa? Thanks!
Document: I bought this for my mother in the nursing home & she loves it. I pinned it to the arm of her chair & that freed up space on her roll-away table.
works as described. Stays in place and holds all bedside 'stuff'.Could no ask for anything better at this price. Thanks
I was hoping this would fit as an armchair organizer for a person who needed a pocket by his chair to through his kleenex into. I don't know how it would work as a bedside organizer, but didn't work for the armchair.
Doesn't work with sleep-number mattress. I was hoping it could hold the remote and other things. The flap that goes under the mattress does stay in place so it falls down if I put anything in it. It might work with a normal bed.
This little thing is awesome. Dorms are so cramped. This was a great solution and will help with organization. Thanks.
This is great! It is very roomy and able to hold quite a bit. It can even be placed under a sofa cushion for use other than the bedroom.
I received my product in a timely manner. Just starting to use it. Very convenient on the side of the bed, so I don't have items all over the place.Thanks
I love the idea of this. It helps to clear the clutter off both of my childrens night tables. They are more organized and I am not picking stuff off the floor, they have a new sense of responsibiliy. Great idea and thanks!
Just what I needed, helps keep me from always looking for the remote and the portable phone, Thanks, I can also keep up with my glasses. Everything that seem to get lost in the bed under the covers now have a dedicated place.
Sounds like a hassle, but it really wasn't. I love this thing, and even after I move into a larger room, I'm going to use this for SOMEthing, even if it's just remotes at the sofa.
Answer: i guess it depends on the sofa!  as long as there is something heavy to hold that flap down then you should be good.  I actually have mine hanging by my window next to my desk! I just closed the window on the flap.