Programming Reference Manual
 
Syntax
 
IsNull(expr)
 
Description
Return the True if expr is Null.
 
Parameter
Description
expr 
A variant expression to test for Null.
See Also
Example
 
Sub Main
    Dim X As Variant
    Debug.Print IsEmpty(X) 'True
    Debug.Print IsNull(X)  'False
    X = 1
    Debug.Print IsNull(X)  'False
    X = "1"
    Debug.Print IsNull(X)  'False
    X = Null
    Debug.Print IsNull(X)  'True
    X = X*2
    Debug.Print IsNull(X)  'True
End Sub