The Empty keyword is the value that a variable is automatically assigned when it is declared using the Dim statement. It is important to understand that this means that a declared variable does have a value, Empty, even if you have purposely not assigned a value in your code.

You can test whether a variable is empty using the IsEmpty function. Also, Empty is not the same as Null or Nothing.

False

The False keyword has the value of -1. You can use that value as a basis for testing in conditional statements.

Nothing

The Nothing keyword is used to disassociate an object variable from an object. If several object variables refer to the same object, all must be set to Nothing before system resources are released.

You must assign Nothing using the Set keyword.

Code:
<% Set YourObject = Nothing %>

Null

The Null keyword indicates that a variable contains no valid data. You can assign a variable the value of Null and use the IsNull() function to test whether a variable is Null. If you print the variable out, the output should be Null.

Also, Null is not the same as Empty or Nothing.

True

The True keyword has the value of 0. You can use that value as a basis for testing in conditional statements.