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Saturday, 21 April 2012

VBScript Variables

VBScript Variables

Variables in VBScript behave just like those variables you would use in Visual Basic. If you don't know Visual Basic don't worry because we are going to put you through Tizag's Five Minute VBScript Variable Bootcamp.

For those of you who have not used variables before, then you should know that the notion of variables helps to make programs easier to program and to understand. Variables are used to hold information so that it can be reused throughout the program. You can think of variables as a grocery bag and your information you want to store as your groceries. Without the bag it's going to be a pain the bum to drag all that food around!

Declaring Variables in VBScript

When you are going to use a variable in your VBScript code you should first declare it. To declare a variable in VBScript you use the Visual Basic Dim statement:

VBScript Code:

<script type="text/vbscript">
Dim myVariable1
Dim myVariable2
</script>

Display:

Nothing is displayed because we were simply setting up our variables for use!
Note: It is also possible to declare multiple variables in one line. Use the comma "," to separate your multiple variable names.

VBScript Code:

<script type="text/vbscript">
Dim myVariable1, myVariable2
</script>

Display:

VBScript Variables: Setting Values

When you want to set your variable equal to a value you use the equals character "=", also known as the equals operator. The name of your variable appears on the left of the equals, while the value you are setting your variable equal to appears to the right of the equals.
To use your variable, simply type the variable name where you would like to use it. In this example we create two variables, set set one equal to a number and the other equal to a string. We then use the document.write method to print both out to the browser.

VBScript Code:

<script type="text/vbscript">
Dim myVariable1, myVariable2
myVariable1 = 22
myVariable2 = "Howdy"
document.write("My number is " & myVariable1)
document.write("<br />My string is " & myVariable2)
</script>

Display:

My number is 22 My string is Howdy

VBScript Variables: Setting Objects

Setting Objects? Yes, VBScript allows you to use objects in your code. Objects are blobs of code goo that can contain multiple methods and variable. When you want to use these methods and variables you have to use the period operator "." to gain access to them. See our VBScript Syntax lesson for more information.
When you are setting a value to a variable that is actually an object then you must follow some special syntax. The SET keyword lets VBScript know that you are setting your variable equal to an object. In addition to this, you also have to set the variable equal to nothing after you are finished with it! It's a lot of extra work, but it is necessary.
This example shows how to use a fictional class myClass to create an object. For this example to work you would have to create myClass yourself. Going into more detail is behind the scope of this lesson.

VBScript Code:

<script type="text/vbscript">
Dim myFirstObject
SET myFirstObject = New myClass
myFirstObject = nothing
</script>

Display:

Note: Once again, nothing is displayed because we were just showing you how to set and release an object in VBScript!

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