What is a Variable? A variable is a "container" for information you want to store. A variable's value can change during the...
What is a Variable?
A variable is a "container" for information you want to store. A
variable's value can change during the script.
You can refer to a variable by name to see its value or to change its value. In VBScript,
all variables are of type variant, that can store different types of
data.
Rules for Variable Names:
- Must begin with a letter
- Cannot contain a period (.)
- Cannot exceed 255 characters
Declaring Variables
You can declare variables with the Dim, Public or the Private statement. Like this:
dim name name=some value |
Now you have created a variable. The name of the variable is "name".
You can also declare variables by using its name in your script. Like this:
name=some value |
Now you have also created a variable. The name of the variable is "name".
However, the last method is not a good practice, because you can misspell the variable name later
in your script, and that can cause strange results when your script is running.
This is because when you misspell for example the "name" variable to
"nime" the script will automatically create a new variable called
"nime". To prevent your script from doing this you can use the Option Explicit statement.
When you use this statement you will have to declare all your variables with the
dim, public or private statement. Put the Option Explicit statement on the top of your script. Like
this:
option explicit dim name name=some value |
Assigning Values to Variables
You assign a value to a variable like this:
name="Hege" i=200 |
The variable name is on the left side of the expression and the value you want to
assign to the variable is on the right. Now the variable "name" has
the value "Hege".
Lifetime of Variables
How long a variable exists is its lifetime.
When you declare a variable within a procedure, the variable can only be accessed within that procedure. When the procedure exits, the variable is destroyed. These variables are called local variables. You can have local variables with the same name in different procedures, because each is recognized only by the procedure in which it is declared.
If you declare a variable outside a procedure, all the procedures on your page can access it. The lifetime of these variables starts when they are declared, and ends when the page is closed.
When you declare a variable within a procedure, the variable can only be accessed within that procedure. When the procedure exits, the variable is destroyed. These variables are called local variables. You can have local variables with the same name in different procedures, because each is recognized only by the procedure in which it is declared.
If you declare a variable outside a procedure, all the procedures on your page can access it. The lifetime of these variables starts when they are declared, and ends when the page is closed.
Array Variables
Sometimes you want to assign more than one value to a single variable. Then you can create a
variable that can contain a series of values. This is called an array variable. The declaration of
an array variable uses parentheses ( ) following the variable name. In the following example, an array containing
3 elements is declared:
dim names(2) |
The number shown in the parentheses is 2. We start at zero so this array contains 3 elements. This is a fixed-size array.
You assign data to each of the elements of the array like this:
names(0)="Tove" names(1)="Jani" names(2)="Stale" |
Similarly, the data can be retrieved from any element using the index of the particular array element you want.
Like this:
mother=names(0) |
You can have up to 60 dimensions in an array. Multiple dimensions are declared by separating
the numbers in the parentheses with commas.
Here we have a two-dimensional array consisting of 5 rows and 7 columns:
dim table(4, 6) |
