Microsoft® JScript®
indexOf Method
 Language Reference 
Version 1 

See Also                  Applies To

Returns the character position where the first occurrence a substring occurs within a String object.
strVariable.indexOf(substring, startindex)
"String Literal".indexOf(substring, startindex)

The indexOf method syntax has these arguments:

Part Description
substring The substring to search for within the String object.
startindex An optional integer value specifying the index to begin searching within the String object. If omitted, searching begins at the beginning of the string.

The indexOf method returns an integer value indicating the beginning of the substring within the String object. If the substring is not found, a -1 is returned.

If startindex is negative, startindex is treated as zero. If it is larger than the greatest character position index, it is treated as the largest possible index.

Searching is performed from left to right. Otherwise, this method is identical to lastIndexOf.

The following example illustrates the use of the indexOf method:

function IndexDemo(str2)
  var s = str1.indexOf(str2);