Live Form

    <.form for={@form} phx-submit="save_phoenix"
  class="flex flex-col gap-space-lg w-full max-w-xl"
>
  <.number_input field={@form[:value]} class="number-input">
    <:label>Value</:label>
    <:decrement_trigger>
      <.heroicon name="hero-chevron-down" class="icon" />
    </:decrement_trigger>
    <:increment_trigger>
      <.heroicon name="hero-chevron-up" class="icon" />
    </:increment_trigger>
    <:error :let={msg}>
      <.heroicon name="hero-exclamation-circle" class="icon" />
      {msg}
    </:error>
  </.number_input>
  <.action type="submit" class="button ui-accent">
    Submit
  </.action>
</.form>

  

    defmodule MyAppWeb.NumberInputFormLive do
  use MyAppWeb, :live_view

  def mount(_params, _session, socket) do
    phoenix_form =
      Phoenix.Component.to_form(%{"value" => "1234"}, as: :number_input_phoenix, id: "number-input-live-form-phoenix")

    {:ok, assign(socket, :phoenix_form, phoenix_form)}
  end

  def handle_event("save_phoenix", %{"number_input_phoenix" => params}, socket) do
    value = params["value"] || ""

    {:noreply,
     assign(
       socket,
       :phoenix_form,
       Phoenix.Component.to_form(%{"value" => value}, as: :number_input_phoenix, id: "number-input-live-form-phoenix")
     )}
  end
end

  

    <.form
  for={@form}
 
  phx-change="validate_strict"
  phx-submit="save_strict"
  class="flex flex-col gap-space-lg w-full max-w-xl"
>
  <.number_input field={@form[:value]} class="number-input">
    <:label>Value (1–9999)</:label>
    <:decrement_trigger>
      <.heroicon name="hero-chevron-down" class="icon" />
    </:decrement_trigger>
    <:increment_trigger>
      <.heroicon name="hero-chevron-up" class="icon" />
    </:increment_trigger>
    <:error :let={msg}>
      <.heroicon name="hero-exclamation-circle" class="icon" />
      {msg}
    </:error>
  </.number_input>
  <.action type="submit" class="button ui-accent">
    Submit
  </.action>
</.form>

  

    defmodule MyAppWeb.NumberInputFormLive do
  use MyAppWeb, :live_view

  def mount(_params, _session, socket) do
    ecto_form =
      %MyApp.Forms.NumberInputForm{}
      |> MyApp.Forms.NumberInputForm.changeset_validate(%{})
      |> Phoenix.Component.to_form(as: :number_input_ecto, id: "number-input-live-form-ecto")

    {:ok, assign(socket, :ecto_form, ecto_form)}
  end

  def handle_event("validate", %{"number_input_ecto" => params}, socket) do
    changeset =
      %MyApp.Forms.NumberInputForm{}
      |> MyApp.Forms.NumberInputForm.changeset_validate(params)
      |> Map.put(:action, :validate)

    {:noreply,
     assign(
       socket,
       :ecto_form,
       Phoenix.Component.to_form(changeset,
         action: :validate,
         as: :number_input_ecto,
         id: "number-input-live-form-ecto"
       )
     )}
  end

  def handle_event("save", %{"number_input_ecto" => params}, socket) do
    case MyApp.Forms.NumberInputForm.changeset_validate(%MyApp.Forms.NumberInputForm{}, params) do
      %Ecto.Changeset{valid?: true} = changeset ->
        _data = Ecto.Changeset.apply_changes(changeset)

        {:noreply,
         assign(
           socket,
           :ecto_form,
           Phoenix.Component.to_form(
             MyApp.Forms.NumberInputForm.changeset_validate(%MyApp.Forms.NumberInputForm{}, params),
             as: :number_input_ecto,
             id: "number-input-live-form-ecto"
           )
         )}

      changeset ->
        {:noreply,
         assign(
           socket,
           :ecto_form,
           Phoenix.Component.to_form(changeset,
             action: :insert,
             as: :number_input_ecto,
             id: "number-input-live-form-ecto"
           )
         )}
    end
  end
end

  

    defmodule MyApp.Forms.NumberInputForm do
  use Ecto.Schema
  import Ecto.Changeset

  embedded_schema do
    field :value, :float
  end

  def changeset(form, attrs \\ %{}) do
    form
    |> cast(attrs, [:value])
    |> validate_required([:value])
  end

  def changeset_validate(form, attrs \\ %{}) do
    form
    |> cast(attrs, [:value])
    |> validate_required([:value])
    |> validate_number(:value, greater_than_or_equal_to: 1.0, less_than_or_equal_to: 9999.0)
  end
end