Elm Browser.application example with an attempted 'preventDefault'

Main.elm

module Main exposing (main)

import Browser
import Browser.Navigation
import Html exposing (..)
import Html.Attributes exposing (..)
import Html.Events exposing (preventDefaultOn)
import Json.Decode as Json
import Url exposing (Url)


type alias Model =
    { count : Int, key : Browser.Navigation.Key }


initialModel _ _ key =
    ( { count = 0, key = key }, Cmd.none )


type Msg
    = UrlChange Url.Url
    | UrlRequest Browser.UrlRequest
    | Increment
    | Decrement


update : Msg -> Model -> ( Model, Cmd Msg )
update msg model =
    case msg of
        UrlChange url ->
            ( model, Cmd.none )

        UrlRequest request ->
            case request of
                Browser.Internal url ->
                    ( model
                    , Browser.Navigation.pushUrl model.key (Url.toString url)
                    )

                Browser.External url ->
                    ( model
                    , Browser.Navigation.load url
                    )

        Increment ->
            ( { model | count = model.count + 1 }, Cmd.none )

        Decrement ->
            ( { model | count = model.count - 1 }, Cmd.none )


view : Model -> Browser.Document Msg
view model =
    { title = ""
    , body =
        [ div []
            -- This is the important bit. When you click on this link it still loads http://www.example.com when
            -- I think it should be prevented?
            [ a [ href "http://www.example.com", onClickPreventDefault Increment ] [ text "+1" ]
            , div [] [ text <| String.fromInt model.count ]
            ]
        ]
    }

onClickPreventDefault : msg -> Attribute msg
onClickPreventDefault msg =
   preventDefaultOn "click" <| Json.succeed ( msg, True )

main : Program () Model Msg
main =
    Browser.application
        { init = initialModel
        , view = view
        , update = update
        , onUrlChange = UrlChange
        , onUrlRequest = UrlRequest
        , subscriptions = \_ -> Sub.none
        }