•
• VBScript is a scripting languageVBScript is a scripting language
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•Scripting language is a lightweight programmingScripting language is a lightweight programming
language language
•
•VBScript is a light version VBScript is a light version of Microsoft's programmingof Microsoft's programming
language Visual Basic language Visual Basic
•
•VBScript can be used for both client-side and server-sideVBScript can be used for both client-side and server-side
programming. programming.
•
• VBScript is a scripting languageVBScript is a scripting language
•
•Scripting language is a lightweight programmingScripting language is a lightweight programming
language language
•
•VBScript is a light version VBScript is a light version of Microsoft's programmingof Microsoft's programming
language Visual Basic language Visual Basic
•
•VBScript can be used for both client-side and server-sideVBScript can be used for both client-side and server-side
programming. programming.
VBScrip
VBScrip
t
t
V
V
ariable
ariable
s
s
A A variable is a "container" for informatvariable is a "container" for information you want to store.ion you want to store.
Naming RulesNaming Rules::
Must begin with an alphabetic character Must begin with an alphabetic character
Cannot contain a periodCannot contain a period
Cannot exceed 255 charactersCannot exceed 255 characters
Lifetime OF Variables
Local Variables:
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. 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.
Global Variables:
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 script is closed.
Variable (Cont)
Declaration:
Dim Keyword is used to Declare a variable
You can Assign a Value to variable directly (without declaring
a variable). But not a good practice.
Option Explicit Keyword is used to restrict variables to be
declared before their usage.
Example:
Option explicit Dim var_ x
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:
Arrays
An array is a set of variables conveniently packages for
easy handling
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
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 that are passed to it by a calling
procedure
without arguments, must include an empty set of
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
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
Functions
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 ()
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()
some statements End Function
If Condition
If keyword is used for executing a set of code when certain
condition is true.
Endif keyword is used to end the if condition code block.
Syntax:
If <condition> then
Some statements End if
If-Else Condition
if...then...else - use this keyword if you want to select
one of two sets of lines to execute
if...then...elseif - use this keyword if you want to
If-Else Condition (cont.)
Syntax : if <condition> then Some statements Else Some statements end IfIf-Elseif Condition (cont.)
Syntax :
if <condition> then Some statements
Elseif <condition> then Some statements
Else
Some statements end If
Select Case Condition
Select case keyword is used to execute one of many blocks of code.
Syntax
select case <variable>
case <first expected value>
Some statements
case <second expected value>
Some statements ……… ……… case Else Some Statements end select
For Loop
For loop is used to execute set of statements , pre
defined number of iterations.
For … Next keywords are used to implement the For
Loop.
Syntax:
For <Loop initialization state> to <ending condition>
Some Statements
For Loop (cont.)
Step keyword is used to increase or decrease the
counter variable by the specified value.
Syntax
For <Loop initialization state> To <ending condition> Step <Increment/Decrement value>
some statements Next
For Loop (cont.)
You can use for loop in order to repeat a block of code for
each item in a collection, or for each element of an array.
Syntax:
For Each <variable name > in <array Variable Name>
<Some Statements>
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
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
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