Returns string after deleting the substring that begins at the nth character and is of length characters. If n is omitted, it defaults to 1. If you omit length, or if length is greater than the number of characters from n to the end of string, the function deletes the rest of string (including the nth character). The length must be a positive whole number or zero. n must be a positive whole number. If n is greater than the length of string, the function returns string unchanged.