advanced vb script guide

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VBScript

Fundamentals



VBScript Variables

A variable is a convenient placeholder that refers to a computer memory location where we can

store program information that may change during the time our script is running.

Declaring Variables

We declare variables explicitly in our script using the Dim statement,

For example:

Dim city

Dim x

We declare multiple variables by separating each variable name with a comma. For example:

Dim x, Top, Bottom, Left, Right

We can also declare a variable implicitly by simply using its name in our script. That is not

generally a good practice because we could misspell the variable name in one or more places,

causing unexpected results when our script is run. For that reason, the Option Explicit statement is available to require explicit declaration of all variables.

The Option Explicit statement should be the first statement in our script.

Option Explicit

Forces explicit declaration of all variables in a script.

Option Explicit ' Force explicit variable declaration.

Dim MyVar ' Declare variable.

MyInt = 10 ' Undeclared variable generates error.

MyVar = 10 ' Declared variable does not generate error.

Naming Restrictions for Variables

Variable names follow the standard rules for naming anything in VBScript. A variable name:

Must begin with an alphabetic character.

Cannot contain an embedded period.

Must not exceed 255 characters. Must be unique in the scope in which it is declared.



Scope of Variables

o A variable's scope is determined by where you declare it.

o When we declare a variable within a procedure, only code within that procedure can

access or change the value of that variable.

o If we declare a variable outside a procedure, we make it recognizable to all the

procedures in our script. This is a script-level variable, and it has script-level scope.

Assigning Values to Variables

Values are assigned to variables creating an expression as follows:

The variable is on the left side of the expression and the value you want to assign to the variable is on the right.

For example:

B = 200

City = “Hyderabad”

Scalar Variables and Array Variables

A variable containing a single value is a scalar variable.

A variable containing a series of values, is called an array variable.

Array variables and scalar variables are declared in the same way, except that the declaration

of an array variable uses parentheses () following the variable name.

Example:

Dim A(3)

Although the number shown in the parentheses is 3, all arrays in VBScript are zero-based, so

this array actually contains 4 elements.

We assign data to each of the elements of the array using an index into the array. Beginning at

zero and ending at 10, data can be assigned to the elements of an array as follows:

A(0) = 256

A(1) = 324

A(2) = 100

A(3) = 55

Similarly, the data can be retrieved from any element using an index into the particular array

element you want.



For example:

SomeVariable = A(4)

Arrays aren't limited to a single dimension. You can have as many as 60 dimensions, although

most people can't comprehend more than three or four dimensions.

In the following example, the MyTable variable is a two-dimensional array consisting of 6 rows

and 11 columns:

Dim MyTable(5, 10)

In a two-dimensional array, the first number is always the number of rows; the second number

is the number of columns.

Dynamic Arrays

We can also declare an array whose size changes during the time our script is running. This

is called a dynamic array.

The array is initially declared within a procedure using either the Dim statement or using the

ReDim statement.

However, for a dynamic array, no size or number of dimensions is placed inside the parentheses.

For example:

Dim MyArray()

ReDimAnotherArray()

To use a dynamic array, you must subsequently use ReDim to determine the number of

dimensions and the size of each dimension.

In the following example, ReDimsets the initial size of the dynamic array to 25. A subsequent

ReDim statement resizes the array to 30, but uses the Preserve keyword to preserve the contents of the array as the resizing takes place.

ReDimMyArray(25)

ReDim Preserve MyArray(30)



There is no limit to the number of times we can resize a dynamic array, although if we make an

array smaller, we lose the data in the eliminated elements.

VBScript Data Types

VBScript has only one data type called a Variant. A Variant is a special kind of data type that

can contain different kinds of information, depending on how it is used. Because Variant is the only data type in VBScript, it is also the data type returned by all functions in VBScript.

Variant

Beyond the simple numeric or string classifications, a Variant can make further distinctions

about the specific nature of numeric information. For example, we can have numeric

information that represents a date or a time. When used with other date or time data, the

result is always expressed as a date or a time. We can also have a rich variety of numeric

information ranging in size from Boolean values to huge floating-point numbers. These different

categories of information that can be contained in a Variant are called subtypes. Most of the

time, we can just put the kind of data we want in a Variant, and the Variant behaves in a way that is most appropriate for the data it contains.

The following table shows subtypes of data that a Variant can contain.

Subtype Description

Empty Variant is uninitialized. Value is 0 for numeric variables or a zero-length

string ("") for string variables.

Null Variant intentionally contains no valid data.

Boolean Contains either True or False.

Byte Contains integer in the range 0 to 255.

Integer Contains integer in the range -32,768 to 32,767.

Currency -922,337,203,685,477.5808 to 922,337,203,685,477.5807.

Long Contains integer in the range -2,147,483,648 to 2,147,483,647.

Single Contains a single-precision, floating-point number in the range -

3.402823E38 to -1.401298E-45 for negative values; 1.401298E-45 to

3.402823E38 for positive values.

Double Contains a double-precision, floating-point number in the range -

1.79769313486232E308 to -4.94065645841247E-324 for negative

values; 4.94065645841247E-324 to 1.79769313486232E308 for positive

values.

Date (Time) Contains a number that represents a date between January 1, 100 to

December 31, 9999.

String Contains a variable-length string that can be up to approximately 2 billion

characters in length.

Object Contains an object.

Error Contains an error number.

We can use conversion functions to convert data from one subtype to another.



VBScript Operators

Operators are used for performing mathematical, comparison and logical operations.

VBScript has a full range of operators, including arithmetic operators, comparison operators, concatenation operators, and logical operators.

Arithmetic Operators:

Operator Description

1) Exponentiation Operator (^) Raises a number to the power of an exponent.

2) Multiplication Operator (*) Multiplies two numbers.

3) Division Operator (/) Divides two numbers and returns a floating-point result.

4) Integer Division Operator (\) Divides two numbers and returns an integer result.

5) Mod Operator Divides two numbers and returns only the remainder.

6) Addition Operator (+) Sums two numbers.

7) Subtraction Operator (-) Finds the difference between two numbers or indicates the

negative value of a numeric expression.

8) Concatenation Operator (&) Forces string concatenation of two expressions.

Comparison Operators

Used to compare expressions.

Operator Description Operator Description

1) = Equal to 5) <= Less than or equal to

2) <> Not equal to 6) >= Greater than or equal to

3) < Less than 7) Is Object equivalence

4) > Greater than

Concatenation Operators

Operator Description

1) Addition Operator

(+)

Sums two numbers.

If Then

1) Both expressions are numeric Add.

2) Both expressions are strings Concatenate.

3) One expression is numeric and the

other is a string

Add.

2) Concatenation

Operator (&)

Forces string concatenation of two expressions.

mk:@MSITStore:C:\Program%20Files\Mercury%20Interactive\QuickTest%20Professional\help\VBScript56.chm::/html/vsidxarithmetic.htm

mk:@MSITStore:C:\Program%20Files\Mercury%20Interactive\QuickTest%20Professional\help\VBScript56.chm::/html/vsgrpcomparison.htm

mk:@MSITStore:C:\Program%20Files\Mercury%20Interactive\QuickTest%20Professional\help\VBScript56.chm::/html/vsidxconcatenation.htm

mk:@MSITStore:C:\Program%20Files\Mercury%20Interactive\QuickTest%20Professional\help\VBScript56.chm::/html/vsidxlogical.htm



Logical Operators

Operator Description Syntax

Not Performs logical negation on an

expression.

result= Not expression

And Performs a logical conjunction on two

expressions.

result= expression1 And

expression2

Or Performs a logical disjunction on two

expressions.

result= expression1 Or

expression2

Eqv Performs a logical equivalence on two expressions.

result= expression1

Eqvexpression2

Input/ Output Operations

InputBox() Function

Displays a prompt in a dialog box, waits for the user to input text or click a button, and returns

the contents of the text box.

Example:

Dim Input

Input = InputBox("Enter your name")

MsgBox ("You entered: " & Input)

MsgBox Function

Displays a message in a dialog box, waits for the user to click a button, and returns a value

indicating which button the user clicked.

Syntax:

MsgBox(prompt, buttons, title)

Prompt :String expression displayed as the message in the dialog box.

Buttons: the icon style to use.

Title: String expression displayed in the title bar of the dialog box.



Button Settings:

Msgbox Return value

Example:

Dim MyVar

MyVar = MsgBox ("Hello World!", 64, "MsgBox Example")

' MyVar contains either 1 or 2, depending on which button is clicked.



VBScript Constants

A constant is a meaningful name that takes the place of a number or string and never changes.

Creating Constants

We create user-defined constants in VBScript using the Const statement. Using the Const

statement, we can create string or numeric constants with meaningful names and assign them literal values.

Const statement

Declares constants for use in place of literal values.

Example:

ConstMyString = "This is my string."

ConstMyAge = 49

ConstCutoffDate = #6-1-97#

Note thatString literal is enclosed in quotation marks (" ").

Represent Date literals and time literals by enclosing them in number signs (#).

We declare multiple constants by separating each constant name and value with a comma. For example:

Const price= 100, city= “Hyderabad”, x= 27



Conditional Statements

We can control the flow of our script with conditional statements and looping statements.

Using conditional statements, we can write VBScript code that makes decisions and repeats actions. The following conditional statements are available in VBScript:

1) If…Then…Else Statement

2) Select Case Statement

Making Decisions Using If...Then...Else

The If...Then...Else statement is used to evaluate whether a condition is True or False and,

depending on the result, to specify one or more statements to run. Usually the condition is an

expression that uses a comparison operator to compare one value or variable with another.

If...Then...Else statements can be nested to as many levels as you need.

Running a Statements if a Condition is True (single statement)

To run only one statement when a condition is True, use the single-line syntax for the

If...Then...Else statement.

Dim myDate

myDate = #2/13/98#

If myDate< Now Then

myDate = Now

Running Statements if a Condition is True(multiple statements)

To run more than one line of code, we must use the multiple-line (or block) syntax. This syntax

includes the End If statement.

Dim x

x= 20

If x>10 Then

msgbox "Hello Pavan"

msgbox "x value is: "&x

msgbox "Bye Bye"

End If



Running Certain Statements if a Condition is True and Running Others if a Condition is

False

We can use an If...Then...Else statement to define two blocks of executable statements: one

block to run if the condition is True, the other block to run if the condition is False.

Example:

Dim x

x= Inputbox (" Enter a value")

If x>100 Then

Msgbox "Hello Pavan"

Msgbox "X is a Big Number"

Msgbox "X value is: "&X

Else

Msgbox "PAVAN"

Msgbox "X is a Small Number"

Msgbox "X value is: "&X

End If

Deciding Between Several Alternatives

A variation on the If...Then...Else statement allows us to choose from several alternatives.

Adding ElseIf clauses expands the functionality of the If...Then...Else statement so we can

control program flow based on different possibilities.

Example:

Dim x

x= Inputbox (" Enter a value")

If x>0 and x<=100 Then


Msgbox "X is a Small Number"

Msgbox "X value is "&x

Else IF x>100 and x<=500 Then

Msgbox "Hello PAVAN"

Msgbox "X is a Medium Number"

Else IF x>500 and x<=1000 Then


Msgbox "X is a Large Number"

Else

Msgbox "Hello Sir"

Msgbox "X is a Grand Number"

End If

End If

End If



Executing a certain block of statements when two / more conditions are True

(Nested If...)

Example:

Dim State, Region

State=Inputbox ("Enter a State")

Region=Inputbox ("Enter a Region")

If state= "AP" Then

If Region= "Telangana" Then


msgbox "Dist count is 10"

Else if Region= "Rayalasema" Then

msgbox "Hello PAVAN"


Else If Region= "Costal" Then



End If

End If

End If

End If

Making Decisions with Select Case

The Select Case structure provides an alternative to If...Then...ElseIf for selectively

executing one block of statements from among multiple blocks of statements. A Select Case

statement provides capability similar to the If...Then...Else statement, but it makes code more efficient and readable.

Example:

Option explicit

Dim x,y, Operation, Result

x= Inputbox (" Enter x value")

y= Inputbox ("Enter y value")

Operation= Inputbox ("Enter an Operation")

Select Case Operation

Case "add"

Result= cdbl (x)+cdbl (y)


Msgbox "Addition of x,y values is "&Result

Case "sub"

Result= x-y




Msgbox "Substraction of x,y values is "&Result

Case "mul"

Result= x*y


Msgbox "Multiplication of x,y values is "&Result

Case "div"

Result= x/y


Msgbox "Division of x,y values is "&Result

Case "mod"

Result= x mod y


Msgbox "Mod of x,y values is "&Result

Case "expo"

Result= x^y


Msgbox"Exponentation of x,y values is "&Result

Case Else


msgbox "Wrong Operation"

End Select



Other Examples

Write a program for finding out whether the given year is a leap year or not?

Dim xyear

xyear=inputbox ("Enter Year")

If xyear mod 4=0 Then

msgbox "This is a Leap year"

Else

msgbox "This is NOT"

End If

Write a program for finding out whether the given number is, Even number or Odd

number?

Dim num

num=inputbox ("Enter a number")

If num mod 2=0 Then

msgbox "This is a Even Number"

Else

msgbox "This is a Odd Number"

End If

Read two numbers and display the sum?

Dim num1,num2, sum

num1=inputbox ("Enter num1")

num2=inputbox ("Enter num2")

sum= Cdbl (num1) + Cdbl (num2) 'if we want add two strings conversion require

msgbox ("Sum is " &sum)

Read P,T,R values and Calculate the Simple Interest?

Dim p,t, r, si

p=inputbox ("Enter Principle")

t=inputbox ("Enter Time")

r=inputbox ("Enter Rate of Interest")

si= (p*t*r)/100 ' p= principle amount, t=time in years, r= rate of interest

msgbox ("Simple Interest is " &si)

Read Four digit number, calculate & display the sum of the number or display Error

message if the number is not a four digit number?

Dim num, sum

num=inputbox ("Enter a Four digit number")

If Len(num) = 4 Then

sum=0



sum=sum+num mod 10

num=num/10

num= left (num, 3)

sum=sum+num mod 10

num=num/10

num= left (num, 2)

sum=sum+num mod 10

num=num/10

num= left (num, 1)

sum=sum+num mod 10

msgbox ("Sum is " &sum)

else

msgbox "Number, you entered is not a 4 digit number"

End If

Read any Four digit number and display the number in reverse order?

Dim num,rev

num= inputbox("Enter a number")

If len(num)=4 Then

rev=rev*10 + num mod 10

num=num/10

num= left(num,3)


num=num/10

num= left(num,2)


num=num/10

num= left(num,1)


msgbox "Reverse Order of the number is "&rev

Else

msgbox "Number, you entered is not a 4 digit number"

End If

Read 4 subjects marks; calculate the Total marks and grade?

(a) If average marks Greater than or equal to 75, grade is Distinction

b) If average marks Greater than or equal to 60 and less than 75 , then grade is First

c) If average marks Greater than or equal to 50 and less than 60 , then grade is

Second

d) If average marks Greater than or equal to 40 and less than 50 , then grade is Third

e) Minimum marks 35 for any subject, otherwise 'no grade fail')

Dim e,m,p,c, tot

e=inputbox ("Enter english Marks")

m=inputbox ("Enter maths Marks")



p=inputbox ("Enter physics Marks")

c=inputbox ("Enter chemistry Marks")

tot= cdbl(e) + cdbl(m) + cdbl(p) + cdbl(c)

msgbox tot

If cdbl(e) >=35 and cdbl(m) >=35 and cdbl(p) >=35 and cdbl(c) >=35 and tot >=300 Then

msgbox "Grade is Distinction"

else If cdbl(e) >=35 and cdbl(m) >=35 and cdbl(p) >=35 and cdbl(c) >=35 and tot >=240

and tot<300 Then

msgbox "Grade is First"


and tot<240 Then

msgbox "Grade is Second"


and tot<200 Then

msgbox "Grade is Third"

else

msgbox "No Grade, Fail"

End If

End If

End If

End If

Display Odd numbers up to n?

Dim num,n

n=Inputbox ("Enter a Vaule")

For num= 1 to n step 2

msgboxnum

Next

Display Even numbers up to n

Dim num,n



msgboxnum

Next

Display Natural numbers in reverse order up to n?

Dim num,n


For num=n to 1 step -1

msgboxnum

Next



Display Natural numbers sum up to n? (Using For...Next Loop)

Dim num, n, sum

n= inputbox ("Enter a Value")

sum=0


sum= sum+num

Next

msgbox sum

Display Natural numbers sum up to n? (Using While...Wend Loop)

Dim num, n, sum


While num<=cdbl (n)

sum= sum+num

num=num+1

Wend

msgbox sum

Display Natural numbers sum up to n? (Using Do...Until...Loop)

Dim num, n, sum


sum=0

num=1

Do

sum= sum+num

num=num+1

Loop Until num =cdbl (n+1)

msgbox sum

Write a Function for Natural Numbers sum up to n

Function NNumCou (n)

Dim num, sum

sum=0


sum= sum+num

Next

msgbox sum

End Function



Verify weather the entered value is a 10 digit value or not and Numeric value or not?

(using multiple if conditions)

Dim a,x,y,z,num

num=Inputbox ("Enter a Phone Number")

d1= left (num,1)

d10=Right (num,1)

d2=mid (num, 2, len (1))








If len (num) =10 Then

If isnumeric (d1) = "True" and isnumeric (d2) = "True" and isnumeric (d3) = "True" and

isnumeric (d4) = "True"andisnumeric (d5) = "True"andisnumeric (d6) = "True"andisnumeric

(d7) = "True"andisnumeric (d8) = "True"andisnumeric (d9) = "True"andisnumeric (d10) =

"True" Then

msgbox "It is a Numeric Value"

End If

End If

If len (num) <> 10 Then

Msgbox "It is NOT valid Number "

End If



Looping Through Code

Looping allows us to run a group of statements repeatedly.

Some loops repeat statements until a condition is False;

Others repeat statements until a condition isTrue.

There are also loops that repeat statements a specific number of times.

The following looping statements are available in VBScript:

1. Do...Loop: Loops while or until a condition is True.

2. While...Wend: Loops while a condition is True.

3. For...Next: Uses a counter to run statements a specified number of times.

4. For Each...Next: Repeats a group of statements for each item in a collection or each

element of an array.

Using Do Loops

We can use Do...Loop statements to run a block of statements an indefinite number of times. The statements are repeated either while a condition is True or until a condition becomes True.

Repeating Statements While a Condition is True

Repeats a block of statements while a condition is True or until a condition becomes True

a) Do While condition

Statements

-----------

-----------

Loop

Or, we can use this below syntax:

Example:

Dim x

Do While x<5 x=x+1


Msgbox "Hello UFT"

Loop

b) Do

Statements

-----------

-----------

LoopWhile condition



Example:

Dim x

x=1

Do


Msgbox "Hello UFT"

x=x+1

Loop While x<5

Repeating a Statement until a Condition Becomes True

c) Do Until condition

Statements

-----------

-----------

Loop


Example:

Dim x

Do Until x=5 x=x+1

Msgbox "Pavan"

Msgbox "Hello UFT"

Loop


d) Do

Statements

-----------

-----------

LoopUntil condition


Example:

Dim x

x=1

Do

Msgbox “Hello Pavan”

Msgbox "Hello UFT"

x=x+1

Loop Until x=5



While...Wend Statement

Executes a series of statements as long as a given condition is True.

Syntax:

While condition

Statements

-----------

-----------

Wend

Example:

Dim x

x=0

While x<5 x=x+1


msgbox "Hello UFT"

Wend

For...Next Statement

Repeats a group of statements a specified number of times.

Syntax:

Forcounter= starttoend [Stepstep]

statements

Next

Example:

Dim x

For x= 1 to 5 step 1


Next

For Each...Next Statement

Repeats a group of statements for each element in an array or collection.



Syntax:

For Each itemInarray

Statements

Next

Example:

Dim a,b,x (3)

a=20

b=30

x(0)= "Addition is "&a+b

x(1)="Substraction is " & a-b

x(2)= "Multiplication is " & a*b

x(3)= "Division is " & a/b

For Each element In x

msgbox element

Next

Example:

MyArray = Array("one","two","three","four","five")

For Each element In MyArray

msgbox element

Next



VBScript Procedures

In VBScript, there are two kinds of procedures; the Sub procedure and the Functionprocedure.

Sub Procedures

A Sub procedure is a series of VBScript statements (enclosed by Sub and End Sub statements) that perform actions but don't return a value.

A Sub procedure can take arguments (constants, variables, or expressions that are passed by a

calling procedure).

If a Sub procedure has no arguments, its Sub statement must include an empty set of parentheses ().

Syntax:

SubProcedure name ()

Statements

-----------

-----------

End Sub

(Or)

SubProcedure name (argument1, argument2)

Statements

-----------

-----------

End Sub

Example: 1

Sub ConvertTemp()

temp = InputBox("Please enter the temperature in degrees F.", 1)

MsgBox "The temperature is "& Celsius(temp) & " degrees C."

End Sub



Function Procedures

A Function procedure is a series of VBScript statements enclosed by the Function and End

Function statements.

A Function procedure is similar to a Sub procedure, but can also return a value.

A Function procedure can take arguments (constants, variables, or expressions that are passed to it by a calling procedure).

If a Function procedure has no arguments, its Function statement must include an empty set of parentheses.

A Function returns a value by assigning a value to its name in one or more statements of the procedure. The return type of a Function is always a Variant.

Syntax:

FunctionProcedure name ()

Statements

-----------

-----------

End Function

Or

FunctionProcedure name (argument1, argument2)

Statements

-----------

-----------

End Function



Example: 1

FunctionCelsius(fDegrees)

Celsius = (fDegrees - 32) * 5 / 9

End Function

Example: 2

Functioncal(a,b,c)

cal = (a+b+c)

End Function

Using Sub and Function Procedures in Code

A Function in our code must always be used on the right side of a variable assignment or in an expression.

For example:

Temp = Celsius(fDegrees)

-Or-

MsgBox "The Celsius temperature is "& Celsius(fDegrees) & " degrees."

To call a Sub procedure from another procedure, type the name of the procedure along with values for any required arguments, each separated by a comma.

The Call statement is not required, but if you do use it, you must enclose any arguments in

parentheses.

The following example shows two calls to the MyProc procedure. One uses the Call statement in the code; the other doesn't. Both do exactly the same thing.

Call MyProc(firstarg, secondarg)

MyProcfirstarg, secondarg

**Notice that the parentheses are omitted in the call when the Call statement isn't used.



ByRef and ByVal Parameters

When you call a subroutine or function, each argument can be passed by

reference or by value.

When an argument is passed by reference, the called procedure can change the value of

the variable. The change persists after the procedure is called.

When an argument is passed by value, any changes that the called procedure makes to

the value of the variable do not persist after the procedure is called.

In a Sub or Function declaration, each parameter can be specified as ByRef or ByVal. If

neither is specified, the default is ByRef.

If ByVal is specified, the corresponding argument is always passed by value when the

subroutine is called.

Below are few simple but quite important differences between passing values byByRef or

ByVal.

ByRef ByVal

Function fun_1( ByRef var_1)

var_1= var_1+ 1

End Function

Dim x: x = 3

'Pass parameter to the function ByRef

fun_1 x

MsgBox x

Result is 4

Function fun_1( ByVal var_1)

var_1= var_1+ 1

End Function

Dim x: x = 3

'Pass parameter to the function ByVal

fun_1 x

MsgBox x

Result is 3

Another way to pass parameter ByRef

Function fun_1( var_1)

var_1= var_1+ 1

End Function

Dim x: x = 3

'Pass parameter to the function ByRef

call fun_1 (x)

MsgBox x

Result is 4

Another way to pass parameter ByVal

Function fun_1( var_1)

var_1= var_1+ 1

End Function

Dim x: x = 3

'Pass parameter to the function ByVal

call fun_1 ((x))

MsgBox x

Result is 3

Function abc(a)

if Not IsArray(a) Then Exit Function

a(0) = "Text"

Function abc(a)

if Not IsArray(a) Then Exit Function

a(0) = "Text"



End Function

Dim w(2), x

For x = 0 To 2

W(x)= x

Next

call abc(w)

for i=0 to UBOUND (w)

Wscript.Echo w(i)

Next

Shows Text,1 and 2

End Function

Dim w(2), x

For x = 0 To 2

W(x)= x

Next

call abc((w))

for i=0 to UBOUND (w)

Wscript.Echo w(i)

Next

Shows 0,1 and 2

Example 1 - passing arguments by ByRef and ByVal

Sub PassArgs(ByRef x, ByVal y, z)

x = 10

y = 11

z = 12

End Sub

Dim a, b, c

PassArgs a, b, c

Msgbox a „shows 10

Msgbox b „shows empty messagebox

Msgbox c „shows 12

Here 3 global variables are used as arguments. The first parameter is declared ByRef, and so

the variable becomes 10 when the assignment statement x= 10 executes. The second

parameter is declared ByVal, and so the varibale b is unaltered by the PassArgs procedure. The

third parameter uses default parameter passing. Because the argument is a varibale, the

argument is passed by reference, and the assignment statement z= 12 does alter the value of

the variable c.



x = 10

y = 11

z = 12

End Sub

PassArgs 1, 2, 3

Here three expressions (actually just numbers) are used as arguments. Using expressions as

arguments forces VBScript to pass the arguments by value regardless of the procedure

declaration.





x = 10

y = 11

z = 12

End Sub

Dim a, b, c

PassArgs (a), (b), (c)

Msgbox a „shows empty messagebox

Msgbox b „shows empty messagebox

Msgbox c „shows empty messagebox

For more details about VBScript:

http://msdn.microsoft.com/en-us/library/0ad0dkea(v=vs.84).aspx

http://msdn.microsoft.com/en-us/library/0ad0dkea(v=vs.84).aspx

advanced vb script guide

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