Microsoft® Visual Basic® Scripting Edition
InStr Function 		 Language Reference 
Version 1 

See Also

Description
Returns the position of the first occurrence of one string within another.
Syntax
InStr([start, ]string1, string2[, compare])

The InStr function syntax has these arguments:

Part Description
start Optional. 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.
string1 Required. String expression being searched.
string2 Required. String expression searched for.
compare Optional. Numeric value indicating the kind of comparison to use when evaluating substrings. See Settings section for values. If omitted, a binary comparison is performed.

Settings
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
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
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.