In JavaScript null is not a "reference to a non-existing object" or a "null pointer" like in some other languages.

Let age = null;
  • The special NULL value represents a variable with no value.
  • NULL is the only possible value of type null.
  • The special null value does not belong to any type of those described above.

A variable is considered to be null if

  • It has been assigned the constant NULL.
  • It has not been set to any value yet.
  • It has been unset().


$var = NULL;       

There is only one value of type null, and that is the case-insensitive constant NULL.

NULL — Structure map

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NULL — Related pages: