May 13, 2021 VBScript
| Keyword | describe |
|---|---|
| Empty |
Used to indicate a variable value that is not initialized.When the variable is created for the first time or when the variable value is set to empty, the variable value is not initialized and the variable is assigned.
Example:
Notice: This is different from NULL!! |
| IsEmpty |
It is used to test whether a variable is not initialized. Example: IF (ISEMPTY (X)) 'variable X is not initialized? |
| Nothing |
Used to indicate an uninitialized object value, or separate object variables from objects for release system resources.
Example: set myObject = Nothing |
| Is Nothing |
Used to test if a value is an object that is initialized.
Example: IF (myObject is nothing "Is it not set? Notice: If you compare a value with Nothing, you will not get the correct result!Example: if (myObject = Nothing) 'is always an error! |
| Null |
Used to indicate that variable does not contain valid data.
NULL sets the value to "invalid", and EMPTY indicates that the value "is not set". Notice: This is different from EMPTY or NOTHING!! Example: x = NULL 'X does not contain valid data |
| IsNull |
Used to test if a value contains invalid data.
Example: IF (isnull (x)) 'X is invalid? |
| True | Used to indicate a Boolean condition is correct (TRUE is -1) |
| False | Used to indicate that a Boolean condition is incorrect (FALSE is 0) |