If you notice the garage door goes up about a foot and stops, you might have a broken spring. You can check by looking on the top part of the garage door and notice 1 or 2 springs, check that they are not broken or notice a gap in the spring.
If you see that is broken do not try to help the door up or try to pull the emergency chord and lift it.
Garage Doors are very heavy and average about 200 lbs.
It is very dangerous to lift the garage door and try to keep it open.
If it slips it can really hurt and worst case scenario kill somebody.
So please, DO NOT OPEN A GARAGE DOOR WITH A BROKEN SPRING.