Сообщение от Help

public indexOf(value:String, [startIndex:Number]) : Number

Searches the string and returns the position of the first occurrence of value found at or after startIndex within the calling string. This index is zero-based, meaning that the first character in a string is considered to be at index 0--not index 1. If value is not found, the method returns -1.

Availability: ActionScript 1.0; Flash Player 5

Parameters
value:String - A string; the substring to search for.

startIndex:Number [optional] - An integer specifying the starting index of the search.

Returns
Number - The position of the first occurrence of the specified substring or -1.