elm button - 1

elm button example extend

{- 
  Step 1, just trying to make the "-" button red. http://elm-lang.org/examples/buttons
  -- import that Html.Attributes module
  -- define the style
  -- add the style attribute to the button

  Step 2, How do I make the "-" button turn red on odd numbers, and green on even numbers?
  
-}

import Html exposing (..)
import Html.App exposing (beginnerProgram)
import Html.Events exposing (onClick)
import Html.Attributes exposing (..)


redStyle : Attribute msg
redStyle =
  style
    [ ("backgroundColor", "red")
    ]

greenStyle : Attribute msg
greenStyle =
  style
    [ ("backgroundColor", "green")
    ]

main =
  beginnerProgram { model = 0, view = view, update = update }


view model =
  div []
    [ button [ Style, onClick Decrement ] [ text "-" ]
    , div [] [ text (toString model) ]
    , button [ onClick Increment ] [ text "+" ]
    ]


type Msg = Increment | Decrement


update msg model =
  case msg of
    Increment ->
      model + 1
      Style redStyle

    Decrement ->
      model - 1