The GOSUB statement causes execution of a local subroutine, after which execution will continue with the next line of code.
The label should refer to an existent label within the current source code. This label denotes the start of a local subroutine. Labels can be numeric or alphanumeric but an alphanumeric label must be terminated with a colon when used to denote the start of a local subroutine. Numeric labels can be terminated with a colon but it is not mandatory. The use of the colon in the GOSUB statement is optional.