The ON … GOTO|GOSUB construct has multiple use cases:

• ON <value> GOTO|GOSUB is used for multiple branching
• ON ERROR GOTO is used for error trapping
• ON <event> GOSUB is used for interrupt handling

ON <value> GOTO|GOSUB <label> [, <label> ...]
ON ERROR GOTO <label>
ON TIMER|RASTER|SPRITE|BACKGROUND GOSUB <label>

For more details, refer to:

• Control Flow Statements
• Error Handling
• Interrupts