VBScript InStr function
Definition and Usage
The InStr function can return the position of the first occurrence of a string within another string.
The InStr function can return the following values:
- If string1 is "" (zero length) - 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 in string1, InStr returns the position of the first occurrence of the matching string.
- If start > Len(string1) - InStr returns 0
Tip:See also InStrRev function.
Syntax
InStr([start,]string1,string2[,compare])
| Parameters | Description |
|---|---|
| start | Optional. Specifies the starting position of each search. The default is the first character. If the compare parameter is specified, this parameter must also be specified. |
| string1 | Required. The string to be searched for. |
| string2 | Required. The string to be searched. |
| compare |
Required. Specifies the type of string comparison to use. The default is 0. The following values can be used:
|
Instance
Example 1
dim txt,pos txt="This is a beautiful day!" pos=InStr(txt,"his") document.write(pos)
Output:
2
Example 2
dim txt,pos txt="This is a beautiful day!" 'A textual comparison starting at position 4' pos=InStr(4,txt,"is",1) document.write(pos)
Output:
6
Example 3
dim txt,pos txt="This is a beautiful day!" 'A binary comparison starting at position 1' pos=InStr(1,txt,"B",0) document.write(pos)
Output:
0
