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Appendix D

VBScript Language Reference

This appendix summarizes the statements, functions, and operators used in the Visual Basic Scripting Edition.
Category/Keyword Arithmetic Type Usage
Atn Function Returns the arctangent of a number
Atn(number)
Cos Function Returns the cosine of an angle
Cos(number)
Exp Function Returns a number raised to a power
Exp(number)
Log Function Returns the logarithm of a number
Log(number)
Randomize Statement Primes the internal random number
generator
Randomize
Rnd Function Returns a random number
Rnd
Sin Function Returns the sine of an angle
Sin(number)
Sqr Function Returns the square root of a number
Sqr(number)
Tan Function Returns the tangent of an angle
Tan(number)
Array handling
Dim Statement Declares an array
Dim arrayname([subscripts])
Erase Statement Clears the contents of an array
Erase arrayname
IsArray Function Returns True if var is an array, and False
if not.
IsArray(var)
LBound Function In VBScript, always returns 0
Lbound(arrayname)
Preserve Statement Copies the contents of a dynamic array
to a resized dynamic array
Redim Preserve arrayname(subscripts)
ReDim Statement Declares a dynamic array or redimensions
a dynamic array (see Preserve)
ReDim arrayname() or
ReDim arrayname([subscripts])
UBound Statement Returns the largest subscript of an
array
Ubound(arrayname)
Assignment
= Operator Assigns a value to a variable or property
variable = value
Set Statement Assigns an object reference to a variable
Set variable = object
Comment
Rem Statement Declares the following line as a comment
to be ignored by the language engine
Rem comment_text
Constants/Literals
Empty Literal Declares a special uninitialized variable value
variable = Empty
False Constant A Boolean value representing 0
variable = False
Nothing Literal Used to disassociate an object reference
from a variable; used in conjunction
with Set
Set variable = Nothing
Null Literal Represents no valid data
variable = Null
True Constant Boolean value representing -1
variable = True
Conversions
Abs Function Returns the unsigned (absolute) value of
a number
Abs(number)
Asc Function Returns the ANSI/ASCII code of a character
Asc(string)
CBool Function Returns a Boolean subtype Variant
value from any valid expression
CBool(expression)
CByte Function Returns a Byte subtype Variant
value from any valid expression
CByte(expression)
CDate Function Returns a Date subtype Variant
value from any valid date expression
CDate(expression)
CDbl Function Returns a Double Precision subtype
Variant value from any valid numeric
expression
CDbl(expression)
Chr Function Returns the character corresponding to
the ANSI or ASCII code
Chr(number)
CInt Function Returns an Integer subtype Variant
value from any valid numeric expression
CInt(expression)
CLng Function Returns a Long Integer subtype Variant
value from any valid numeric expression
CLng(expression)
CSng Function Returns a Single Precision subtype
Variant value from any valid numeric
expression
CSng(expression)
CStr Function Returns a String subtype Variant
value from any valid expression
CStr(expression)
DateSerial Function Returns a Date subtype Variant value from valid year, month, and day values
DateSerial(year,month,day)
DateValue Function Returns a Date subtype Variant value from any valid date expression
DateValue(expression)
Hex Function Returns a String subtype Variant value
representing the hexadecimal value of a number
Hex(number)
Int Function Returns an Integer subtype Variant value
rounded down from the number supplied
Int(number)
Fix Function Returns an Integer subtype Variant value
rounded up from the number supplied
Fix(number)
Oct Function Returns a String subtype Variant value
representing the octal value of a number
Hex(number)
Sgn Function Returns an Integer subtype Variant value
representing the sign of a number
Sgn(number)
values > 0 return 1
values = 0 return 0
values < 0 return -1
TimeSerial Function Returns a Date subtype Variant value from
valid hour, minute, and second values
TimeSerial(hour,minute,second)
TimeValue Function Returns a Date subtype Variant value from any valid time expression
TimeValue(expression)
Dates and Times
Date Function Returns the current system date
Date()
DateSerial Function Returns a Date subtype Variant value from
valid year, month, and day values.
DateSerial(year,month,day)
DateValue Function Returns a Date subtype Variant
value from any valid date expression.
DateValue(expression)
Day Function Returns an Integer subtype Variant value
representing the day (1-31) from a
valid date expression
Day(dateexpression)
Hour Function Returns an Integer subtype Variant value
representing the hour (0-23) from a valid time expression
Hour(timeexpression)
Minute Function Returns an Integer subtype Variant value
representing the minute (0-60) from a
valid time expression
Minute(timeexpression)
Month Function Returns an Integer subtype Variant value
representing the month (1-12) from a
valid date expression
Month(dateexpression)
Now Function Returns the current date and time of the
system
Now()
Second Function Returns an Integer subtype Variant value
representing the second (0-60) from a
valid time expression
Second(timeexpression)
Time Function Returns the current system time
Time()
TimeSerial Function Returns a Date subtype Variant from
valid hour, minute, and second values
TimeSerial(hour,minute,second)
TimeValue Function Returns a Date subtype Variant value from any valid time expression
TimeValue(expression)
Weekday Function Returns an Integer subtype Variant value
between 1 and 7 representing the day of
the week, starting at Sunday, from a
date expression
Weekday(dateexpression)
Year Function Returns an Integer subtype Variant value
representing the year from a valid date expression
Year(dateexpression)
Declarations
Dim Statement Declares a variable
Dim variable
End Statement Declares the end of a Sub procedure or
function
End Sub
End Function
Exit Statement Use with Do, For, Function, or Sub to
prematurely exit the routine
Exit Do/For/Function/Sub
Function Statement Declares a function and the argument
list passed into the function, and declares the end of a function; also used with Exit to prematurely end a function
Function functionname(argumentlist)
Exit Function
End Function
Public variable
Sub Statement Declares a custom procedure or event
handler and the argument list, if any, and declares the end of a custom procedure or event handler; also used with Exit to prematurely end a custom procedure or event handler
Sub subroutinename([argumentlist])
Exit Sub
End Sub
Error Handling
Clear Method A method of the Err object to reset the
Err.Number property to 0
Err.Clear
Description Property A property of the Err object that contains a description of the last error as specified in the Err.Number property
Err.Description
Err Object An object containing information about
the last error
Err.property|method
On Error Statement Used in conjunction with Resume Next to
continue execution with the line directly following the line in which the error occurred
On Error Resume Next
Raise Method A method of the Err object used to
simulate the occurrence of an error
specified by number
Err.Raise(errornumber)
Number Property A property of the Err object that
contains the error code for the last
error, or 0 if no error has occurred
Err.Number
Source Property Returns the name of the object or
application that raised the error
Err.Source
Input/Output
InputBox Function Displays a dialog box to allow user input
InputBox(caption[,title][,value][,x][,y])
MsgBox Function Displays a dialog box
MsgBox(prompt[, definition][, title])
Operators
+ Operator Addition of two numerical expressions
result = expr1 + expr2
And Operator Logical conjunction operator
If expression AND expression Then
/ Operator Division operator
result = expression / expression
= Operator Equality operator
If expression = expression Then
Eqv Operator Logical equivalence operator
If expression Eqv expression Then
^ Operator Exponentiation operator
result = expression ^ expression
> Operator Greater than comparison
If expression > expression Then
>= Operator Greater than or equal to comparison
If expression >= expression Then
Imp Operator Logical implication
If expression Imp expression Then
<> Operator Inequality comparison
If expression <> expression Then
\ Operator Integer division operator
result = expression \ expression
< Operator Less than comparison
If expression < expression Then
<= Operator Less than or equal to comparison
If expression <= expression Then
Mod Operator Modulus arithmetic; returns only the
remainder of a division of two numbers
result = expression mod expression
* Operator Multiplication
result = expression * expression
- Operator Subtraction
result = expression - expression
Or Operator Logical disjunction
If expression Or expression Then
& Operator Concatenation of two string values
result = string & string
Xor Operator Logical exclusion
If expression Xor expression Then
Options
Option Statement Forces a compile-time error if an
Explicit undeclared variable is found
Option Explicit
Program Flow
Call Statement Passes execution to a sub-routine or
event handler; also can be used to replicate
the actions of the user
Call myroutine()
Call cmdbutton_OnClick()
Do...Loop Statement Repeats code while a condition is met or
until a condition is met
Do While condition
...
Loop
or
Do Until condition
...
Loop
or
Do
...
Loop While condition
or
Do
...
Loop Until condition
For...Next Statement Repeats a block of code until the
counter reaches a given number
For counter = lower to upper [step]
...
Next
If...Then...Else Statement Conditional execution of code
If condition Then
... (if condition met)
Else
... (if condition not met)
End If
Select Case Statement Selective execution of code, where
testexpression must match expression
Select Case testexpression
Case expression
...
Case expression
...
Case Else
End Select
While...Wend Statement Execution of a code block while a condition is met
While expression
...
Wend
Strings
InStr Function Returns the starting point of one string
within another string, or 0 if not found
result = InStr(start,searched,sought)
LCase Function Converts a string to lowercase
result = LCase(string)
Left Function Returns the n leftmost character of a string
result = LCase(string)
Len Function Returns the length of a string
result = Len(string)
LTrim Function Removes all leading spaces
result = LTrim(string)
Mid Function Returns a string of length L, starting at S within string
result = Mid(string, S, L)
Right Function Returns the rightmost n character
result = Right(string, n)
RTrim Function Removes all trailing spaces from a string
result = RTrim(string)
Space Function Returns a string consisting of n spaces
result = Space(n)
StrComp Function Returns an Integer subtype Variant
representing the result of a comparison
of two strings
result = StrComp(string1, string2)
string1 < string2 returns -1
string1 < string2 returns 0
string1 < string2 returns 1
String Function Returns a string consisting of character
C, of length L
result = String(L, C)
Trim Function Removes both leading and trailing spaces
result = Trim(string)
UCase Function Returns a string as uppercase alphabetical characters
result = UCase(string)
Variants
IsArray Function Returns True (-1) if expression is an
array, and False (0) if not
result = IsArray(expression)
IsDate Function Returns True (-1) if expression is a valid date and False (0) if not
result = IsDate(expression)
IsEmpty Function Returns True (-1) if expression equates
to an Empty subtype and False (0) if not
result = IsEmpty(expression)
IsNull Function Returns True (-1) if expression equates
to a Null subtype and False (0) if not
result = IsNull(expression)
IsNumeric Function Returns True (-1) if expression is a valid numeric expression and False (0) if not
result = IsNumeric(expression)
VarType Function Returns an integer representing the subtype
of a Variant
result = VarType(expression)

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