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 Chapter values
`DateSerial(`year`,`month`,`Chapter`)`
`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 Chapter values.
`DateSerial(`year`,`month`,`Chapter`)`
`DateValue`	Function	Returns a Date subtype `Variant`
value from any valid date expression.
`DateValue(`expression)
`Chapter`	Function	Returns an Integer subtype `Variant` value
representing the Chapter (`1-31`) from a
valid date expression
`Chapter(`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)
`WeekChapter`	Function	Returns an Integer subtype `Variant` value
between `1` and `7` representing the Chapter of
the week, starting at SunChapter, from a
date expression
`WeekChapter(`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`)`