isset vs empty vs is_null

Question

I\'m trying to write a script that when a user uploads a file and does not enter a name an error is returned. I\'ve tried using is_null, empty, and isset and they all do not

Answer 1

In these php functions empty(),isset() & is_null are mainly used to test the variables.but each functions have different functionalists.

Credits : empty() , isset(), is_null()