Why there is gravitation in earth only and not beyond that

the gravitational force between two objects is proportional to the mass of each, and inversely proportional to the distance between them. It is usually written like this (G is the gravitational constant):

F = Gm1m2/r^2
where G is the universal gravitational constant
G = 6.6726 x 10-11N-m2/kg2
as the objects get further apart, the gravitational pull gets much weaker but it is always there

Cause of gravitation is not known. In recent experiments; some dark matter is found. In next two years scientist may found out, whether the said dark matter is responsible for weight and gravity of any object. Name of experiment is large hydrogen collider.

Every object has gravity. I do, you do and so on. The bigger the object the more gravity it has. The earth is big enough to hold us down and the moon in orbit.

gravitational force also exist outside earth but it is too weak there

Everything that has a mass no matter where in the universe has a gravitational pull

There is gravity everywhere in the universe.

Because there is only gravitational force inside of the earth magnetic field , beyond that there is none..
Until you find another object like planets or starts , then the gravitational force of them will pull you