ON GOSUB and ON GOTO Statements
In Reality mode, the
ON GOSUB and
ON GOTO statements operate as described. In any other mode, the 
operation is as follows:
  - If expression evaluates to a value that has a corresponding statement 
label, control is transferred to that statement label.
 
  - If expression evaluates to a value less than 1 or greater than the number 
of statement labels, execution continues with the statement following the
  ON GOSUB or
  ON GOTO statement.