What are garage door openers? Garage doors can be controlled by either a push button or pull string. Garage doors are usually hung from overhead tracks, mounted on wheels, or rolled into panels that run through the garage walls. If you've just had a new garage entryway that you have installed, it's a good idea to install an opener that will not only allow you to open and close your garage doors, but also serve as a safety device to prevent the door slamming when the pressure from a car or truck gets under it.