ON...GOSUB and ON...GOTO Statement Details
 
Syntax 1
  ON expression GOSUB {line-number-list | line-label-list}
 
Syntax 2
  GOTO {line-number-list | line-label-list }
 
The expression argument can be any numeric expression (expression is
rounded to an integer before the ON...GOSUB or ON...GOTO is evaluated).
The line-number-list or line-label-list consists of a list of line numbers
or line labels, separated by commas. The value of expression determines
which line the program branches to. For example, if the value is 3, the
third line specified in the list is the destination of the branch.
 
The value of expression should be greater than or equal to 1 and less
than or equal to the number of items in the list. If the value falls
outside this range, one of the following results occurs:
 
  Value                          Result
  Number equal to 0 or greater   Control drops to the next BASIC
  than number of items in list   statement.
 
  Negative number or             An error message appears that reads
  number greater than 255        "Illegal function call."
 
 
You may mix line numbers and labels in the same list.
 
  Note: ON...GOTO statement accepts a maximum of 60 line labels or line
        numbers. The SELECT CASE statement provides a more powerful,
        convenient, and flexible way to do multiple branches.