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VBScript InStr Function

VBScript Reference 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:

  • 0 = vbBinaryCompare - Perform a binary comparison
  • 1 = vbTextCompare - Perform a textual comparison

Examples

Example 1

<script type="text/vbscript">

txt="This is a beautiful day!"
document.write(InStr(txt,"beautiful"))

</script>

The output of the code above will be:

11

Try it yourself »

Example 2

Finding the letter "i", using different starting positions:

<script type="text/vbscript">

txt="This is a beautiful day!"
document.write(InStr(1,txt,"i") & "<br />")
document.write(InStr(7,txt,"i") & "<br />")

</script>

The output of the code above will be:

3
16

Try it yourself »

Example 3

Finding the letter "t", with textual, and binary, comparison:

<script type="text/vbscript">

txt="This is a beautiful day!"
document.write(InStr(1,txt,"t",1) & "<br />")
document.write(InStr(1,txt,"t",0) & "<br />")

</script>

The output of the code above will be:

1
15

Try it yourself »
VBScript Reference Complete VBScript Reference

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