VBScript InStr Function

Returns the position of the first occurrence of one string within another.

Syntax: VBScript InStr Function

InStr([start, ]string1, string2[, compare])

Arguments: VBScript InStr Function

start

The numeric expression that sets the starting position for each search. If omitted, search begins at the first character position. If start contains Null, an error occurs. The start argument is required if compare is specified. Optional.

string1

The string expression being searched. Required.

string2

The string expression searched for. Required.

compare

A numeric value indicating the kind of comparison to use when evaluating substrings. See Settings section for values. If omitted, a binary comparison is performed. Optional.

Settings : VBScript InStr Function

The compare argument can have the following values:

Constant	Value	Description
vbBinaryCompare	0	Perform a binary comparison.
vbTextCompare	1	Perform a textual comparison.

Return Values: VBScript InStr Function

The InStr function returns the following values:

If	InStr returns
string1 is zero-length	0
string1 is Null	Null
string2 is zero-length	Start
string2 is Null	Null
string2 is not found	0
string2 is found within string1	Position at which match is found
start > Len(string2)	0

Remarks: VBScript InStr Function

The following examples use InStr to search a string:

Dim SearchString, SearchChar, MyPos

SearchString ="XXpXXpXXPXXP" ' String to search in.

SearchChar = "P" ' Search for "P".

MyPos = Instr(4, SearchString, SearchChar, 1) ' A textual comparison starting at position 4. Returns 6.

MyPos = Instr(1, SearchString, SearchChar, 0) ' A binary comparison starting at position 1. Returns 9.

MyPos = Instr(SearchString, SearchChar) ' Comparison is binary by default (last argument is omitted). Returns 9.

MyPos = Instr(1, SearchString, "W") ' A binary comparison starting at position 1. Returns 0 ("W" is not found).

Note

The InStrB function is used with byte data contained in a string. Instead of returning the character position of the first occurrence of one string within another, InStrB returns the byte position.