substr « String « Flash / Flex / ActionScript

1.Working with Substring Values: substr
2.Optionally omit the second parameter, substr returns a substring starting at the specified index and going to the end of the original string.
3.Specifying a negative value simply counts backward from the end of the string where -1 is the last character.
4.substring method returns a substring starting with the starting index specified and containing all the characters up to, but not including, the ending index.
5.Use lastIndexOf to get the file name without extension name