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CVBScript Syntax Quick Reference

VBScript is composed of a great deal of syntax you need to keep straight. You will probably use many elements of the syntax so often that you will easily remember what they do. However, even an experienced programmer uses some of the syntax elements infrequently. When you come across those elements in your code or strain to remember if you have the syntax exactly right, a good reference can serve as a welcome relief.

Languages such as Visual Basic 4.0 come complete with a very useful context-sensitive help facility. VBScript provides no such inherent support. It is a hosted language that comes along for the ride with the environment that supports it, such as a browser. It is not a separate product with its own development environment and the help that is typical of such an environment. You can turn to other places for help on the Internet, however. At the time of this writing, Microsoft had a very helpful VBScript language reference that could be reached under http://www.microsoft.com/vbscript.

This appendix is intended to supplement the VBScript information available from the Web location. Unlike some of the other language references available, the information in this appendix is presented in a strict alphabetical fashion, intermixing functions, statements, See Prior Notes, and major properties in the same list. A brief description of each element is provided, but it's not enough to replace the official reference material—just enough to give you a quick high-level understanding of what that element does.

You'll develop a common way to refer to information as you work your way through a new book or sample programs. You might find a language element that is unfamiliar, but all you need to do to quickly get back on course is see a brief description of what it does and find out if it is a property, function, or other type of construct. This appendix can serve as a quick first resort for such information.

Symbol




Type




Description




+ (addition)

Operator

Adds two numbers together. You can also use this to concatenate strings.

' (comment indicator)

Keyword

What follows this symbol on the line is a comment.

" (double quote)

Keyword

Denotes the start and end of a literal string.

& (string concatenation)

Operator

Performs the concatenation of two string expressions.

/ (division, floating point)

Operator

Divides two numbers and returns a floating-point result.

\ (division, integer)

Operator

Divides two numbers and returns an integer result.

= (equals) comparison

Checks whether two expressions are equivalent.

^ (exponent)

Operator

Raises a number to the power of an exponent.

> (greater than)

Comparison

Checks whether the left-side expression is greater than the right-side expression.

>= (greater than or equal)

Comparison

Checks whether the left-side expression is greater than or equal to the right-side expression.

< (less than)

Comparison

Checks whether the left-side expression is less than the right-side expression.

<= (less than or equal)

Comparison

Checks whether the left-side expression is less than or equal to the right-side expression.

_ (line continuation character)

Keyword

Indicates that the current line continues onto the next line.

* (multiplication)

Operator

Multiplies two numbers.

- (subtraction or negation)

Operator

Finds the difference between two numbers, or when applied to one operand, treats it as a negative value.

: (colon)


Indicates line separation, as in A = A + 1 : B = C + 1.

<> (not equal)

Comparison

Checks whether two expressions are not equivalent.

Abs

Function

Returns the absolute value of a number.

And

Logical

Performs a logical conjunction on two expressions.

Array

Function

Returns a variant comprising an array.

Asc

Function

Provides the character code corresponding to the first letter in a string as a return code.

AscB

Function

Like Asc, but it returns the first byte rather than the first character of a string.

Atn

Function

Provides the arctangent of a number as a return code.

Call

Statement

Calls a procedure.

CBool

Function

Provides as a return code an expression that has been converted to a variant of subtype Boolean.

Cbyte

Function

Provides as a return code an expression that has been converted to a variant of subtype Byte.

CDate

Function

Provides as a return code an expression that has been converted to a variant of subtype Date.

CDbl

Function

Provides as a return code an expression that has been converted to a variant of subtype Double.

Chr

Function

Provides as a return code the character associated with the ASCII code. This function can return one or two bytes.

ChrB

Function

Returns the byte associated with the ASCII code.

Cint

Function

Provides as a return code an expression that has been converted to a variant of subtype Integer.

Clear

Method for the Err object

Results in resetting all of the Err objects properties to a no-error state.

CLng

Function

Provides as a return code an expression that has been converted to a variant of subtype Long.

Cos

Function

Provides as a return code the cosine of an angle.

CSng

Function

Provides as a return code an expression that has been converted to a variant of subtype Single.

CStr

Function

Provides as a return code an expression that has been converted to a variant of subtype String.

CVErr

Function

Provides as a return code a variant of subtype Error containing a user-provided error code.

Date

Function

Returns the current system date.

DateSerial

Function

Provides as a return code a variant of subtype Date for the given month, day, and year.

DateValue

Function

Provides as a return code a variant of subtype Date for the given string.

Day

Function

Provides as a return code a whole number of 1 through 31, representing the day of the month for the given date string.

Description

Property for the Err object

The string that describes the current error.

Dim

Statement

Declares variables.

Do...Loop

Statement

Repeats a block of code while a condition is True or until a condition becomes True.

Empty

Literal

Signifies that a variable is uninitialized.

Erase

Statement

Reinitializes fixed-size array elements and frees the storage space of dynamic arrays.

Err

Object

Provides information about run-time errors.

Eqv

Logical operator

Performs logical equivalence for the two expressions provided as operands.

Exit Do

Statement

Exits a Do. . .Loop code block.

Exit For

Statement

Exits a For. . .Next code block.

Exit Function

Statement

Exits a function.

Exit Sub

Statement

Exits a procedure.

Exp

Function

Returns e (the base of natural logarithms) raised to a power.

Fix

Function

Provides the integer portion of a number as a return code; if the number is negative, it provides the first number greater than the operand.

For. . .Next

Statement

Repeats a group of statements a designated number of times.

For Each. . .Next

Statement

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

Function

Statement

Declares a procedure-level block of code that returns a value when called.

HelpContext

Property for the Err object

The context ID in a corresponding help file for the current error.

HelpFile

Property for the Err object

The corresponding help file for the current error.

Hex

Function

Provides as a return code a string representing the hexadecimal value of a number.

Hour

Function

Provides as a return code a whole number from 0 through 23, representing the hour of the day.

If. . .Then. . .Else

Statement

Executes a group of statements, depending on the value of an expression.

Imp

Logical operator

Performs a logical implication on the two operands provided.

InputBox

Function

Displays a dialog box with a prompt, appropriate buttons, and an input text box and then returns the input text and button response to calling program.

Int

Function

Provides the integer portion of a number as a return code; if the number is negative, it provides first number less than the operand.

InStr

Function

Provides the position indicator of the first character of the target string within the search string.

InstrB

Function

Provides the position indicator of the first byte of the target string within the search string.

Is

Operator

Compares two object reference variables.

IsArray

Function

Provides as a return code a Boolean value signifying whether a variable is an array.

IsDate

Function

Provides as a return code a Boolean value signifying whether an expression can be converted to a date.

IsEmpty

Function

Provides as a return code a Boolean value signifying whether a variable has been initialized.

IsError

Function

Provides as a return code a Boolean value signifying whether an expression is an error value.

IsNull

Function

Provides as a return code a Boolean value signifying whether an expression contains no valid data (Null).

IsNumeric

Function

Provides as a return code a Boolean value signifying whether an expression can be evaluated as a number.

IsObject

Function

Provides as a return code a Boolean value signifying whether an expression represents an OLE automation object.

LBound

Function

Provides as a return code the smallest available subscript for the stated dimension of an array.

Lcase

Function

Provides as a return code a string that has been converted to lowercase.

Left

Function

Provides as a return code a specified number of characters from the left side of a string.

Len

Function

Provides as a return code the number of characters in a string or the number of bytes required to store a variable.

LenB

Function

Provides as a return code the number of bytes in a string or the number of bytes required to store a variable.

Log

Function

Provides as a return code the natural logarithm of a number.

Ltrim

Function

Provides a string that has leading (leftmost) spaces removed.

Mid

Function

Provides as a return code a described number of characters from a string.

Minute

Function

Provides as a return code a whole number from 0 through 59, representing the minute of the hour.

Mod

Operator

Divides two numbers and returns only the remainder.

Month

Function

Provides as a return code a whole number from 1 through 12, representing the month of the year.

MsgBox

Function

Shows a given prompt in a message dialog box with a button and returns the user's button response.

Not

Logical operator

Checks for logical not equivalent condition.

Nothing

Literal

Removes reference and frees memory.

Now

Function

Returns the current setting of your computer's system date and time.

Null

Literal

Indicates no valid data state, as opposed to Empty, which indicates no data was ever assigned.

Number

Property for the Err object

The numeric error code for the current error.

Oct

Function

Provides as a return code a string representing the octal value of a number.

On Error Resume Next

Statement

Indicates that if an error occurs, control should resume at next statement.

Option Explicit

Statement

Indicates that variables must be declared.

Or

Operator

Performs a logical disjunction on two expressions.

Raise

Method for the Err object

Forces a run-time error to be raised.

Randomize

Statement

Starts a sequence for the random-number generator.

ReDim

Statement

Allocates or reallocates storage space and declares dynamic-array variables at the procedure level.

Rem

Statement

Used to include comments in a program. The single quote that achieves the same purpose is used more often.

Right

Function

Provides as a return code a described number of characters from the right side of a string.

Rnd

Function

Provides a random number as a return code.

Rtrim

Function

Provides a string that has trailing (rightmost) spaces removed.

Second

Function

Provides as a return code a whole number from 0 through 59, representing the second of the minute.

Set

Statement

Assigns an object reference.

Sgn

Function

Provides as a return code an integer disclosing the sign of a number.

Sin

Function

Provides as a return code the sine of an angle.

Source

Property for the Err object

The source of the error for the current error.

Space

Function

Returns the given number of spaces.

Sqr

Function

Provides as a return code the square root of a number.

Static

Statement (Procedure-level)

Declares a persistent variable. Contents will be retained from one call to the next.

StrComp

Function

Returns a value signifying the outcome of a string comparison.

String

Function

Returns a repeating character string of the number of characters described.

Sub

Statement

Declares procedures that do not provide a return code.

Tan

Function

Provides as a return code the tangent of an angle.

Time

Function

Returns a variant of subtype Date showing the current system time.

TimeSerial

Function

Returns a variant of subtype Date comprising the time for a specific hour, minute, and second.

TimeValue

Function

Returns a variant of subtype Date containing the time.

Trim

Function

Provides as a return code a duplicate of a string without leading spaces (LTrim), trailing spaces (RTrim), or both leading and trailing spaces (Trim).

Ubound

Function

Provides as a return code the largest available subscript for the indicated dimension of an array.

Ucase

Function

Returns a string that has been converted to uppercase.

Val

Function

Returns the numbers enclosed in a string. Not supported in current beta.

VarType

Function

Returns a value disclosing the subtype of a variable.

vbAbort*

(See footnote*)

Applies to the MsgBox function; Value = 3 indicates abort.

vbAbortRetryIgnore

(See footnote*)

Applies to the MsgBox function; Value = 2 displays Abort, Retry, and Ignore buttons

vbApplicationModal

(See footnote*)

Applies to the MsgBox function; Value = 0 indicates that the application is modal. The user must respond to the message box before continuing work in the current application.

vbArray

(See footnote*)

Applies to the VarType function; Value = 8192 indicates array.

vbBoolean

(See footnote*)

Applies to the VarType function; Value = 11 indicates Boolean.

vbByte

(See footnote*)

Applies to the VarType function; Value = 17 indicates byte.

vbCancel

(See footnote*)

Applies to the MsgBox function; Value = 2 indicates cancel.

vbCr

(See footnote*)

General purpose; indicates carriage-return character.

vbCritical

(See footnote*)

Applies to the MsgBox function; Value = 16 displays critical message icon.

vbCrLf

(See footnote*)

General purpose; indicates carriage-return and line-feed characters.

vbCurrency

(See footnote*)

Applies to the VarType function; Value = 6 indicates currency.

vbDataObject

(See footnote*)

Applies to the VarType function; Value = 13 indicates non-OLE automation object.

vbDate

(See footnote*)

Applies to the VarType function; Value = 7 indicates date.

vbDefaultButton1

(See footnote*)

Applies to the MsgBox function; Value = 0 indicates the first button is the default.

vbDefaultButton2

(See footnote*)

Applies to the MsgBox function; Value = 256 indicates the second button is the default.

vbDefaultButton3

(See footnote*)

Applies to the MsgBox function; Value = 512 indicates the third button is the default.

vbDouble

(See footnote*)

Applies to the VarType function; Value = 5 indicates a double-precision, floating-point number.

vbEmpty

(See footnote*)

Applies to the VarType function, Value = 0 indicates empty.

vbError

(See footnote*)

Applies to the VarType function; Value = 10 indicates error.

vbExclamation

(See footnote*)

Applies to the MsgBox function; Value = 48 displays the warning message icon.

vbFalse

(See footnote*)

General purpose; indicates Boolean value represented by 0.

vbFriday

(See footnote*)

Applies to the Weekday function; Value = 6 indicates Friday.

vbIgnore

(See footnote*)

Applies to the MsgBox function; Value = 5 indicates ignore.

vbInformation

(See footnote*)

Applies to the MsgBox function; Value = 64 displays information message icon.

vbInteger

(See footnote*)

Applies to the VarType function; Value = 2 indicates integer.

vbLf

(See footnote*)

General purpose; indicates line-feed character.

vbLong

(See footnote*)

Applies to the VarType function; Value = 3 indicates long integer.

vbMonday

(See footnote*)

Applies to the Weekday function; Value = 2 indicates Monday.

vbNo

(See footnote*)

Applies to the MsgBox function; Value = 7 indicates no.

vbNull

(See footnote*)

Applies to the VarType function; Value = 1 indicates null.

vbObject

(See footnote*)

Applies to the VarType function; Value = 9 indicates OLE automation object.

vbObjectError

(See footnote*)

Indicates an object-generated error.

vbOK

(See footnote*)

Applies to the MsgBox function; Value = 1 indicates OK.

vbOKCancel

(See footnote*)

Applies to MsgBox function; Value = 1 displays OK and Cancel buttons.

vbOKOnly

(See footnote*)

Applies to the MsgBox function; Value = 0 displays OK button only.

vbQuestion

(See footnote*)

Applies to the MsgBox function; Value = 32 displays warning query icon.

vbRetry

(See footnote*)

Applies to the MsgBox function; Value = 4 indicates retry.

vbRetryCancel

(See footnote*)

Applies to the MsgBox function; Value = 5 displays retry and cancel buttons.

vbSaturday

(See footnote*)

Applies to the Weekday function; Value = 7 indicates Saturday.

vbSingle

(See footnote*)

Applies to the VarType function; Value = 4 indicates single-precision, floating-point number.

vbString

(See footnote*)

Applies to the VarType function; Value = 8 indicates string.

vbSunday

(See footnote*)

Applies to the Weekday function; Value = 1 indicates Sunday.

vbSystemModal

(See footnote*)

Applies to the MsgBox function; Value = 4096 indicates system modal. All applications are suspended until the user responds to the message box.

vbThursday

(See footnote*)

Applies to the Weekday function; Value = 5 indicates Thursday.

vbTrue

(See footnote*)

General purpose; indicates Boolean value represented by -1.

vbTuesday

(See footnote*)

Applies to the Weekday function; Value = 3 indicates Tuesday.

vbUseSystem

(See footnote*)

Applies to the Weekday function; Value = 0 uses the NLS API setting.

vbVariant

(See footnote*)

Applies to the VarType function; Value = 12 indicates variant.

vbWednesday

(See footnote*)

Applies to the Weekday function; Value = 4 indicates Wednesday.

vbYes

(See footnote*)

Applies to the MsgBox function; Value = 6 indicates yes.

vbYesNo

(See footnote*)

Applies to the MsgBox function; Value = 4 displays yes and no buttons.

vbYesNoCancel

(See footnote*)

Applies to the MsgBox function; Value = 3 displays yes, no, and cancel buttons.

Weekday

Function

Returns a whole number showing the day of the week.

While. . .Wend

Statement

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

Xor

Logical operator

Performs logical exclusion on the operands.

Year

Function

Returns a whole number showing the year for the date string representation.

*The symbols with the vb prefix are values expected by various VBScript functions. In Visual Basic these are intrinsic contants. In VBScript, you must declare these as variables if you wish to treat them as constants since there is no direct constant support.

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