VBScript InStrFunction

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The InStr function returns the position of the first occurrence of one string within another.

The InStr function returns 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 of the first matching string found
  • If start > Len(string1) - InStr returns 0

Tip:See the InStrRev function.

Syntax

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

Parameter Description
start Optional. Specifies the starting position for each search. The default starting position is the first character (1). This parameter is required if the compare parameter has been specified.
string1 Required. The string to be searched.
string2 Required. The string expression to search for.
compare Optional. Specifies the type of string comparison to use. Default is 0.

Can use the following values:

  • 0 = vbBinaryCompare - Performs a binary comparison
  • 1 = vbTextCompare - Performs a text comparison

Examples

Example 1

<script type="text/vbscript">

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

</script>

The output of the above example is:

11

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Example 2

Find 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 above example is:

3
16

Try it yourself »

Example 3

Find the letter "t" using text 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 above example is:

1
15

Try it yourself »
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