= How to enable Form features =

== input[type=number] ==

If you have never done anything for input[type=number], it lacks the following features:
Spin button UI
Number localization

=== Spin button UI ===

This is optional. Opera has similar UI, but IE10 has no spin button.
If you want the spin button UI, implement RenderTheme::adjustInnerSpinButtonStyle and paintInnerSpinButtonStyle.
Test: fast/forms/number/number-{appearance,spinbutton}*.html

=== Number localization ===

This is optional. IE10 localizes numbers, but Opera doesn't.
This feature requires Locale class implementation. If your port is using WebCore/platform/text/LocaleNone.cpp, this feature is disabled. Use WebCore/platform/text/{LocaleICU.cpp,mac/LocaleMac.mm,win/LocaleWin.cpp}, or implement your own Locale class.
Test: fast/forms/number/number-l10n-input.html

== Interactive form validation ==

1. Implement WebCore/page/ValidationMessageClient.h for your port
2. Set it to PageClients::validationMessageClient
3. Page::settings()->setInteractiveFormValidationEnabled(true)

Doing step 3 without step 1 and 2 enables platform-neutral form validation UI. But it has some unresolvable bugs.  You should provide your ValidationMessageClient.

== input[type=color] ==

Enable ENABLE_INPUT_TYPE_COLOR flag, and implement ChromeClient::createColorChooser.

== Date, datetime-local, month, time, week input types ==

WebCore provides two UI types for them.
Multiple-fields UI (ENABLE_INPUT_MULTIPLE_FIELDS_UI flag)
Chooser-only UI (no ENABLE_INPUT_MULTIPLE_FIELDS_UI flag)

In the multiple-fields UI, users can specify values quickly with keyboard or mouse input. This UI is not suitable for mobile devices with touch input. Optionally we can provide platform-specific chooser dialog UI.
The Chooser-only UI is simple. We provide only platform-specific chooser dialog UI.

=== Chooser-only UI ===

1. Enable ENABLE_INPUT_TYPE_FOO without ENABLE_INPUT_MULTIPLE_FIELDS_UI
2. Implement Locale class (See "Number localization" section)
3. Implement ChromeClient::openDateTimeChooser

=== Multiple-fields UI ===

1. Enable ENABLE_INPUT_TYPE_FOO and ENABLE_INPUT_MULTIPLE_FIELDS_UI
2. Implement Locale class (See "Number localization" section)
2. Implement RenderTheme::adjustInnerSpinButonStyle and paintInnerSpinButtonStyle
3. Optionally, provide chooser dialog UI.
  3.1 Implement RenderTheme::supportsCalendarPicker so that it returns true for supported input types.
  3.2 Implement ChromeClient::openDateTimeChooser
  Note that WebCore has calendar chooser implementation built with HTML. It supports date type, month type, week type, and year-month-day part of datetime-local type. It requires ENABLE_CALENDAR_PICKER and ENABLE_PAGE_POPUP. This implementation doesn't support time type and the time part of datetime-local type.
If we add their support in the future, ENABLE_CALENDAR_PICKER can be used for the chooser-only UI too.

== input[type=datetime] ==

Do not enable it.  You can not make an appropriate UI with the current WebCore code.

== Datalist element ==

This depends on input types.

=== Text field types ===

1. Enable ENABLE_DATALIST_ELEMENT
2. Implement RenderTheme::supportsDataListUI so that it returns true for supported types.
3. In WebKit layer, hook keyboard input, focus, or touch events for a target text field, and show UI to choose values of HTMLInputElement::dataList.

=== Range type ===

1. Enable ENABLE_DATALIST_ELEMENT
2. Implement RenderTheme::supportsDataListUI so that it returns true for range type.
3. Implement/override RenderTheme::slideTickSnappingThreshold, sliderTickSize, sliderTickOffsetFromTrackCenter.

=== Color type ===

1. Enable ENABLE_DATALIST_ELEMENT
2. Implement RenderTheme::supportsDataListUI so that it returns true for color type.
3. Your ColorChooser implementation should respect ColorChooserClient::shouldShowSuggestions and suggestions.

=== Date, datetime-local, month, time, week types ===

1. Enable ENABLE_DATALIST_ELEMENT
2. Implement RenderTheme::supportsDataListUI so that it returns true for supported types.
3. Implement ChromeClient::openDateTimeChooser so that it handles DateTimeChooserParameters::suggestionValues.