VBScript

VBScript

What is VBScript?

• VBScript is a scripting language.
• A scripting language is an interpreted programming language.
• VBScript is based in part on Microsoft's programming language Visual Basic
• While it doesn't offer the same functionality of Visual Basic, it does provide a powerful tool that can be used to add interaction to web pages.

What is VBScript used for?

• VBScript is used to give functionality and interaction to web pages.
• VBScript can be used for client-side scripting.
• If VBS is used for client side scripting, only Internet Explorer can interpret it (down side). VBScript is a Microsoft technology that requires Microsoft's IE.
• VBS can also be used for server-side scripting. This requires the use of a Microsoft web server such as Personal Web Server (PWS), or Internet Information Server (IIS) and a packaging such as Active Server Pages (ASP).

What can be done with VBScript?

Interact with the user - For example, you can ask the user for their name and print a custom message with it on a webpage such as "Hello"

Form validation - Validate data entered by the user. For example, you can check to make sure that certain fields in a form were actually filled out, or that a piece of data contains the required amount of characters

Perform calculations - You can use VBScript to perform a range of mathematical calculations ranging from simple arithmetic to complex formulas

Act upon events - Specify code to run when certain events occur. For example, when the user clicks a button you can instruct VBScript to display a message in an alert box

VBScript Variables

As with algebra, VBScript variables are used to hold values or expressions.
A variable can have a short name, like x, or a more descriptive name, like carname.
Rules for VBScript variable names:

• Must begin with a letter 
• Cannot contain a period (.)
• Cannot exceed 255 characters

VBScript Sub Procedures

A Sub procedure:

• is a series of statements, enclosed by the Sub and End Sub statements
• can perform actions, but does not return a value
• can take arguments

VBScript Function Procedures

A Function procedure:

• is a series of statements, enclosed by the Function and End Function statements
• can perform actions and can return a value
• can take arguments that are passed to it by a calling procedure
• without arguments, must include an empty set of parentheses ()
• returns a value by assigning a value to its name