What does this statement mean?

Hi all,

can anyone tell me as to what is meant by this statement.

DATA : event TYPE REF TO CL_HTMLB_EVENT.

Statement 1:

event = cl_htmlb_manager=>get_event( runtime->

server- >request)

Data :button_event TYPE REF TO CL_HTMLB_EVENT_BUTTON.

Statement 2:

button_event ?= event.

Please explain to me statement 1 and ststement 2.

Regards,

Saurabh