1 ON
2 ERROR
 The ON ERROR statement transfers program control to a  specified  line
 or program module.  If an error is pending when the ON ERROR statement
 executes, control is transferred immediately.  Otherwise,  control  is
 transferred  when an error occurs.  For new program development, it is
 recommended that you use WHEN blocks.

3 GOBACK
 After BASIC executes an ON ERROR GO BACK in  a  subprogram  or  DEF,
 control transfers to the calling (main) program when an error occurs
 under certain conditions.

 Example

 ON ERROR GO BACK

4 Syntax

     { ONERROR  }
     { ON ERROR } GO BACK

3 GOTO
 The ON ERROR GOTO statement transfers program control to a specified
 line or label in the current program unit when an error occurs under
 certain conditions.

 Example

  5     ON ERROR GOTO 19000

4 Syntax

     { ONERROR  } { GO TO }
     { ON ERROR } { GOTO  } target

3 GOTO 0
 The ON ERROR GOTO 0 statement disables user error handling and  passes
 control  to the BASIC error handler when an error occurs under certain
 conditions.

 Example

 ON ERROR GOTO 0

4 Syntax

              { GO TO }
     ON ERROR { GOTO  } 0

2 GOSUB
 The ON GOSUB statement transfers program control  to  one  of  several
 subroutines, depending on the value of a control expression.

 Example

 150    ON Control% GOSUB 100, 200, 300 OTHERWISE 500

3 Syntax

     ON int-exp GOSUB target,...  [ OTHERWISE target ]

2 GOTO
 The ON GOTO statement transfers program  control  to  one  of  several
 lines, depending on the value of a control expression.

 Example

 330    ON Index% GOTO 700, 800, 900 OTHERWISE 1000

3 Syntax

                { GO TO }
     ON int-exp { GOTO  } target,... [ OTHERWISE target ]