Keywords

Empty
The Empty keyword is used to indicate an uninitialized variable value. This is not the same thing as Null.
False
The False keyword has a value equal to 0.
Nothing
The Nothing keyword in VBScript is used to disassociate an object variable from any actual object.
Null
The Null keyword is used to indicate that a variable contains no valid data. This is not the same thing as Empty.
True
The True keyword has a value equal to -1.