VBScript in a Nutshell, 2nd Edition

Name

InStr, InStrB Functions

Syntax

InStr([start, ]stringtosearch, stringtofind[, comparemode])

start

Use: Optional

Data Type: Numeric

The starting position for the search.

stringtosearch

Use: Required

Data Type: String

The string being searched.

stringtofind

Use: Required

Data Type: String

The string being sought.

comparemode

Use: Optional

Data Type: Integer

The type of string comparison.

Return Value

A Long.

Description

Finds the starting position of one string within another.

Rules at a Glance

• The return value of InStr is influenced by the values of stringtosearch and stringtofind, as shown in the following table:

Condition	InStr return value
stringtosearch is zero-length	0
stringtosearch is Null	Null
stringtofind is zero-length	start
stringtofind is Null	Null
stringtofind is not found	0
stringtofind is found within stringtosearch	Position at which the start of stringtofind is found
start > len(stringtofind)	0

• If the start argument is omitted, InStr commences the search with the first character of stringtosearch.

• If the start argument is Null, an error occurs.

• You must specify a start argument if you are specifying a comparemode argument.

• VBScript supports intrinsic constants for comparemode, as follows:

  Comparison mode	Value	Constant
  Binary (default)	0	vbBinaryCompare
  Text—case- insensitive	1	vbTextCompare

  In effect, a binary comparison means that the search for stringtofind in stringtosearch is case-sensitive. A text comparison means that the search for stringtofind in stringtosearch is not case-sensitive. ...