fib.erl

-module(fib).

-export([main/1]).

add_entry(DomNode, Text) ->
  NewNode = dom_document:create_element(<<"div">>),
  dom_element:set_inner_text(NewNode, Text),
  dom_element:append_child(DomNode, NewNode).

fib(DomNode, N, B, A) ->
  add_entry(DomNode, erlang:integer_to_binary(A)),
  case N =< 0 of
    true -> ok;
    false -> fib(DomNode, erlang:'-'(N, 1), erlang:'+'(A, B), B)
  end.

main([Arg | []]) ->
  Node = dom_document:get_element_by_id(<<"lam">>),

  T0 = date:now(),
  add_entry(Node, << "Started at: ", (erlang:integer_to_binary(T0))/binary >>),

  % work!
  fib(Node, erlang:list_to_integer(Arg), 1, 0),

  T1 = date:now() - T0,
  add_entry(Node, << "Finished in: ", (erlang:integer_to_binary(T1))/binary >>).