< Complete VBScript Reference
The InStr function returns the position of the first occurrence of one string within another.
The InStr function can return the following values:
- If string1 is "" - InStr returns 0
- If string1 is Null - InStr returns Null
- If string2 is "" - InStr returns start
- If string2 is Null - InStr returns Null
- If string2 is not found - InStr returns 0
- If string2 is found within string1 - InStr returns the position at which match is found
- If start > Len(string1) - InStr returns 0
Tip: Also look at the InStrRev function
Syntax
InStr([start,]string1,string2[,compare])
| Parameter | Description |
|---|---|
| start | Optional. Specifies the starting position for each search. The search begins at the first character position (1) by default. This parameter is required if compare is specified |
| string1 | Required. The string to be searched |
| string2 | Required. The string expression to search for |
| compare | Optional. Specifies the string comparison to use.
Default is 0 Can have one of the following values:
|
Examples
Example 1
<%
txt="This is a beautiful day!"
response.write(InStr(txt,"beautiful"))
%>
The output of the code above will be:
11
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Example 2
Finding the letter "i", using different starting positions:
<%
txt="This is a beautiful day!"
response.write(InStr(1,txt,"i") & "<br />")
response.write(InStr(7,txt,"i") & "<br />")
%>
The output of the code above will be:
3
16
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Example 3
Finding the letter "t", with textual, and binary, comparison:
<%
txt="This is a beautiful day!"
response.write(InStr(1,txt,"t",1) & "<br />")
response.write(InStr(1,txt,"t",0) & "<br />")
%>
The output of the code above will be:
1
15
Show Example »
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