คำหลัก VBScript
คำหลัก VBScript
| Keyword | Description |
|---|---|
| Empty |
Used to indicate an uninitialized variable value. A variable value is uninitialized when it is first created and no value is assigned to it, or when a variable value is explicitly set to empty. Example: Note: This is not the same as Null!! |
| IsEmpty | Used to test if a variable is uninitialized. Example: If (IsEmpty(x)) 'is x uninitialized? |
| Nothing | Used to indicate an uninitialized object value, or to
disassociate an object variable from an object to release system resources. Example: Set myObject=Nothing |
| Is Nothing | Used to test if a value is an initialized object.
Example: If (myObject Is Nothing) 'is it unset? Note: If you compare a value to Nothing, you will not get the right result! Example: If (myObject = Nothing) 'always false! |
| Null | Used to indicate that a variable contains no valid data.
One way to think of Null is that someone has explicitly set the value to "invalid", unlike Empty where the value is "not set". Note: This is not the same as Empty or Nothing!! Example: x=Null 'x contains no valid data |
| IsNull | Used to test if a value contains invalid data.
Example: if (IsNull(x)) 'is x invalid? |
| True | Used to indicate a Boolean condition that is correct |
| False | Used to indicate a Boolean condition that is not correct (False has a value of 0) |