VB Script

• VBScript stands for Visual Basic Scripting, is a scripting

language was launched by Microsoft in1996.

VB Scripting language is a lightweight programming

language.

VBScript can be used to write both client-side and server-side scripting.

• VBScript supports only one Data type called ‘Variant’

•A Variant is a special type of data that can contain

different kinds of information, depending upon how it is

used.

•A variant behaves as a number when it is used in a

numeric context and as a string when used in string

context.

VBScript VariablesA variable is a "container" /Placeholder that refers to a memory

location,that stores program information that may change at

run time.

Variable Declaration:

Dim :Variable declared with Dim at script level are available

To all procedures within the script.

Public: Variables are available to all procedures in all scripts.

Private: Variables are available only to the scripts in which they

are declared.

Naming Rules:

Must begin with an alphabetic character

Cannot contain an embedded period

Cannot exceed 255 characters

Must be unique within its scope in which it is declared.

Implicit Declaration:

You can Assign a Value to variable directly (without declaring a

variable). But not a good practice, because you may misspell the

variable name in one or more places, causing unexpected result

when your script is run.

Example:

Dim var_ x

var_x=1

Constants The values that do not alter during the entire

execution of the program are called as constants.

Const keyword is used to declare constants.

It is necessary to initialize the Constant during its declaration.

You cannot change the value of constants in later script.

Syntax:

const x=1

const my string=“This is my string”

Arrays

A Variable containing single value is called scalar variable.

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.

Arrays (cont.) The declaration of an array variable uses parentheses ( )

following the variable name.

Example:

dim names(2)

names(0)=“Ali“

names(1)=“Imran“

names(2)=“Khan"

Arrays (cont.)

An array can be multi dimensional.

There can be 60 (maximum) dimensions in an array.

Multiple dimensions are declared by separating the numbers in the parentheses with commas.

ProceduresA 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 that are passed to it by a calling procedure

without arguments, must include an empty set of parentheses ()

Procedures (Cont) Sub Keyword is Used to declare a procedure.

End Sub Keyword is Used to defining the ending boundary of a procedure.

Call Keyword is Used in order to invoke a procedure.

Syntax:

Sub mysub()

some statements

End Sub

Call mysub()

Procedures (Cont) Procedure can take arguments that are passed to it by

calling that procedure .

Syntax:

Sub procedure name(arg1,arg2)

some statements

End Sub

Call mysub(value1,value2)

FunctionsA 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

Functions (Cont) Function Keyword is Used to declare a Function.

End Function Keyword is Used to defining the ending boundary of a Function.

<Function Name> is Used in order to invoke a Function.

Syntax:

Function myfunc()

myfunc=value

some statements

End Function

myfunc

If Condition Using If statement we can execute a single or block of

statements when a conditionis true.

Ex:-If i=0 Then

msgbox "Hello"i=i+1

End If

If-Else Condition

Execute a block of statement when condition is true, otherwise execute another block of statements when condition false.

If i=2 then

msgbox”Hello world”

Else

Msgbox”Thank You”

End if

If-Elseif Condition (cont.)

Decide among several alternates.

if payment="Cash" then

msgbox "You are going to pay cash!"

elseif payment="Visa" then

msgbox "You are going to pay with visa."

elseif payment="AmEx" then

msgbox "You are going to pay with American Express." else

msgbox "Unknown method of payment.“

end If

Select Case Condition Using this statement one of several groups of statements

are executed based on the expression value. Example: You can use the SELECT statement if you want to select one of many blocks of code to execute.

Select case paymentCase " Cash "msgbox " You are going to pay cash "Case " Visa "msgbox " You are going to pay with Visa "Case " AmEx"msgbox " You are going to pay with American Express"Case Elsemsgbox " Unknown method of payment"

End Select

For LoopA For loop is used for situations when you need to do something over and over again until some condition statement fails.

Ex:-

For count=0 to 3Print (count)

Next

For Each Loop It is useful when you want to go through every element

in an array but you do not know how many elements are there inside the array.

Ex:-

Dim a(2)a(0)= " Pen "a(1) =" Register"a(2)= " Copy"For Each item In a

Print(item)Next

Do-while loop

Do-while keywords are used to execute specified code for a set of times (until a condition remains true or a condition becomes false).

Syntax

Do While <Condition for loop>

Some Statements

Loop

Do-while loop (cont.)

Do-While can also used in following syntax:

Do

some Statements

Loop While i>10

Do-Until Loop

Do – Until keyword is used for repeating some set of statements until a certain condition is true.

Syntax:

Do Until <Condition>

some statmemts

Loop

Do-Until Loop (cont.) Do-Until can also used in following syntax:

Do

some statements

Loop Until <Condition>

Built in Functions

VB Script provides several built in functions that can be used just by calling them.

Few Examples:

Date

Time

Int