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# VBScript InStr Function * * Complete VBScript Reference Manual](#) * * * The InStr function returns the position of the first occurrence of one string within another string. 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 where the match was found * If start > Len(string1) - InStr returns 0 **Tip:** See also the InStrRev function. ### Syntax InStr([start,]string1,string2[,compare]) | Parameter | Description | | :--- | :--- | | start | Optional. Specifies the starting position for each search. The default search starting position is the first character (1). If the compare parameter is specified, this parameter must be included. | | 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. The default is 0. The following values can be used: * 0 = vbBinaryCompare - Performs a binary comparison * 1 = vbTextCompare - Performs a text comparison | ## Examples ## Example 1 txt="This is a beautiful day!" document.write(InStr(txt,"beautiful")) The output of the above example is: 11 [Try it »](#) ## Example 2 Find the letter "i" with different starting positions: txt="This is a beautiful day!" document.write(InStr(1,txt,"i") & "
") document.write(InStr(7,txt,"i") & "
") The output of the above example is: 3 16 [Try it »](#) ## Example 3 Find the letter "t" using text and binary comparison: txt="This is a beautiful day!" document.write(InStr(1,txt,"t",1) & "
") document.write(InStr(1,txt,"t",0) & "
") The output of the above example is: 1 15 [Try it »](#) * * Complete VBScript Reference Manual](#)