VBScript InStr Function
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 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
|
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
|
|