CityApper
/
django
镜像来自 https://github.com/django/django


			
				
					
						
						
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							=======
Widgets
=======

.. module:: django.forms.widgets
   :synopsis: Django's built-in form widgets.

.. currentmodule:: django.forms

A widget is Django's representation of an HTML input element. The widget
handles the rendering of the HTML, and the extraction of data from a GET/POST
dictionary that corresponds to the widget.

The HTML generated by the built-in widgets uses HTML5 syntax, targeting
``<!DOCTYPE html>``. For example, it uses boolean attributes such as ``checked``
rather than the XHTML style of ``checked='checked'``.

.. tip::

    Widgets should not be confused with the :doc:`form fields </ref/forms/fields>`.
    Form fields deal with the logic of input validation and are used directly
    in templates. Widgets deal with rendering of HTML form input elements on
    the web page and extraction of raw submitted data. However, widgets do
    need to be :ref:`assigned <widget-to-field>` to form fields.

.. _widget-to-field:

Specifying widgets
==================

Whenever you specify a field on a form, Django will use a default widget
that is appropriate to the type of data that is to be displayed. To find
which widget is used on which field, see the documentation about
:ref:`built-in-fields`.

However, if you want to use a different widget for a field, you can
use the :attr:`~Field.widget` argument on the field definition. For example::

    from django import forms

    class CommentForm(forms.Form):
        name = forms.CharField()
        url = forms.URLField()
        comment = forms.CharField(widget=forms.Textarea)

This would specify a form with a comment that uses a larger :class:`Textarea`
widget, rather than the default :class:`TextInput` widget.

Setting arguments for widgets
=============================

Many widgets have optional extra arguments; they can be set when defining the
widget on the field. In the following example, the
:attr:`~django.forms.SelectDateWidget.years` attribute is set for a
:class:`~django.forms.SelectDateWidget`::

    from django import forms

    BIRTH_YEAR_CHOICES = ['1980', '1981', '1982']
    FAVORITE_COLORS_CHOICES = [
        ('blue', 'Blue'),
        ('green', 'Green'),
        ('black', 'Black'),
    ]

    class SimpleForm(forms.Form):
        birth_year = forms.DateField(widget=forms.SelectDateWidget(years=BIRTH_YEAR_CHOICES))
        favorite_colors = forms.MultipleChoiceField(
            required=False,
            widget=forms.CheckboxSelectMultiple,
            choices=FAVORITE_COLORS_CHOICES,
        )

See the :ref:`built-in widgets` for more information about which widgets
are available and which arguments they accept.

Widgets inheriting from the ``Select`` widget
=============================================

Widgets inheriting from the :class:`Select` widget deal with choices. They
present the user with a list of options to choose from. The different widgets
present this choice differently; the :class:`Select` widget itself uses a
``<select>`` HTML list representation, while :class:`RadioSelect` uses radio
buttons.

:class:`Select` widgets are used by default on :class:`ChoiceField` fields. The
choices displayed on the widget are inherited from the :class:`ChoiceField` and
changing :attr:`ChoiceField.choices` will update :attr:`Select.choices`. For
example::

    >>> from django import forms
    >>> CHOICES = [('1', 'First'), ('2', 'Second')]
    >>> choice_field = forms.ChoiceField(widget=forms.RadioSelect, choices=CHOICES)
    >>> choice_field.choices
    [('1', 'First'), ('2', 'Second')]
    >>> choice_field.widget.choices
    [('1', 'First'), ('2', 'Second')]
    >>> choice_field.widget.choices = []
    >>> choice_field.choices = [('1', 'First and only')]
    >>> choice_field.widget.choices
    [('1', 'First and only')]

Widgets which offer a :attr:`~Select.choices` attribute can however be used
with fields which are not based on choice -- such as a :class:`CharField` --
but it is recommended to use a :class:`ChoiceField`-based field when the
choices are inherent to the model and not just the representational widget.

Customizing widget instances
============================

When Django renders a widget as HTML, it only renders very minimal markup -
Django doesn't add class names, or any other widget-specific attributes. This
means, for example, that all :class:`TextInput` widgets will appear the same
on your Web pages.

There are two ways to customize widgets: :ref:`per widget instance
<styling-widget-instances>` and :ref:`per widget class <styling-widget-classes>`.

.. _styling-widget-instances:

Styling widget instances
------------------------

If you want to make one widget instance look different from another, you will
need to specify additional attributes at the time when the widget object is
instantiated and assigned to a form field (and perhaps add some rules to your
CSS files).

For example, take the following form::

    from django import forms

    class CommentForm(forms.Form):
        name = forms.CharField()
        url = forms.URLField()
        comment = forms.CharField()

This form will include three default :class:`TextInput` widgets, with default
rendering -- no CSS class, no extra attributes. This means that the input boxes
provided for each widget will be rendered exactly the same::

    >>> f = CommentForm(auto_id=False)
    >>> f.as_table()
    <tr><th>Name:</th><td><input type="text" name="name" required></td></tr>
    <tr><th>Url:</th><td><input type="url" name="url" required></td></tr>
    <tr><th>Comment:</th><td><input type="text" name="comment" required></td></tr>

On a real Web page, you probably don't want every widget to look the same. You
might want a larger input element for the comment, and you might want the
'name' widget to have some special CSS class. It is also possible to specify
the 'type' attribute to take advantage of the new HTML5 input types.  To do
this, you use the :attr:`Widget.attrs` argument when creating the widget::

    class CommentForm(forms.Form):
        name = forms.CharField(widget=forms.TextInput(attrs={'class': 'special'}))
        url = forms.URLField()
        comment = forms.CharField(widget=forms.TextInput(attrs={'size': '40'}))

You can also modify a widget in the form definition::

    class CommentForm(forms.Form):
        name = forms.CharField()
        url = forms.URLField()
        comment = forms.CharField()

        name.widget.attrs.update({'class': 'special'})
        comment.widget.attrs.update(size='40')

Or if the field isn't declared directly on the form (such as model form fields),
you can use the :attr:`Form.fields` attribute::

    class CommentForm(forms.ModelForm):
        def __init__(self, *args, **kwargs):
            super().__init__(*args, **kwargs)
            self.fields['name'].widget.attrs.update({'class': 'special'})
            self.fields['comment'].widget.attrs.update(size='40')

Django will then include the extra attributes in the rendered output:

    >>> f = CommentForm(auto_id=False)
    >>> f.as_table()
    <tr><th>Name:</th><td><input type="text" name="name" class="special" required></td></tr>
    <tr><th>Url:</th><td><input type="url" name="url" required></td></tr>
    <tr><th>Comment:</th><td><input type="text" name="comment" size="40" required></td></tr>

You can also set the HTML ``id`` using :attr:`~Widget.attrs`. See
:attr:`BoundField.id_for_label` for an example.

.. _styling-widget-classes:

Styling widget classes
----------------------

With widgets, it is possible to add assets (``css`` and ``javascript``)
and more deeply customize their appearance and behavior.

In a nutshell, you will need to subclass the widget and either
:ref:`define a "Media" inner class  <assets-as-a-static-definition>` or
:ref:`create a "media" property <dynamic-property>`.

These methods involve somewhat advanced Python programming and are described in
detail in the :doc:`Form Assets </topics/forms/media>` topic guide.

.. _base-widget-classes:

Base widget classes
===================

Base widget classes :class:`Widget` and :class:`MultiWidget` are subclassed by
all the :ref:`built-in widgets <built-in widgets>` and may serve as a
foundation for custom widgets.

``Widget``
----------

.. class:: Widget(attrs=None)

    This abstract class cannot be rendered, but provides the basic attribute
    :attr:`~Widget.attrs`.  You may also implement or override the
    :meth:`~Widget.render()` method on custom widgets.

    .. attribute:: Widget.attrs

        A dictionary containing HTML attributes to be set on the rendered
        widget.

        .. code-block:: pycon

            >>> from django import forms
            >>> name = forms.TextInput(attrs={'size': 10, 'title': 'Your name'})
            >>> name.render('name', 'A name')
            '<input title="Your name" type="text" name="name" value="A name" size="10">'

        If you assign a value of ``True`` or ``False`` to an attribute,
        it will be rendered as an HTML5 boolean attribute::

            >>> name = forms.TextInput(attrs={'required': True})
            >>> name.render('name', 'A name')
            '<input name="name" type="text" value="A name" required>'
            >>>
            >>> name = forms.TextInput(attrs={'required': False})
            >>> name.render('name', 'A name')
            '<input name="name" type="text" value="A name">'

    .. attribute:: Widget.supports_microseconds

       An attribute that defaults to ``True``. If set to ``False``, the
       microseconds part of :class:`~datetime.datetime` and
       :class:`~datetime.time` values will be set to ``0``.

    .. method:: format_value(value)

        Cleans and returns a value for use in the widget template. ``value``
        isn't guaranteed to be valid input, therefore subclass implementations
        should program defensively.

    .. method:: get_context(name, value, attrs)

        Returns a dictionary of values to use when rendering the widget
        template. By default, the dictionary contains a single key,
        ``'widget'``, which is a dictionary representation of the widget
        containing the following keys:

        * ``'name'``: The name of the field from the ``name`` argument.
        * ``'is_hidden'``: A boolean indicating whether or not this widget is
          hidden.
        * ``'required'``: A boolean indicating whether or not the field for
          this widget is required.
        * ``'value'``: The value as returned by :meth:`format_value`.
        * ``'attrs'``: HTML attributes to be set on the rendered widget. The
          combination of the :attr:`attrs` attribute and the ``attrs`` argument.
        * ``'template_name'``: The value of ``self.template_name``.

        ``Widget`` subclasses can provide custom context values by overriding
        this method.

    .. method:: id_for_label(id_)

        Returns the HTML ID attribute of this widget for use by a ``<label>``,
        given the ID of the field. Returns ``None`` if an ID isn't available.

        This hook is necessary because some widgets have multiple HTML
        elements and, thus, multiple IDs. In that case, this method should
        return an ID value that corresponds to the first ID in the widget's
        tags.

    .. method:: render(name, value, attrs=None, renderer=None)

        Renders a widget to HTML using the given renderer. If ``renderer`` is
        ``None``, the renderer from the :setting:`FORM_RENDERER` setting is
        used.

    .. method:: value_from_datadict(data, files, name)

        Given a dictionary of data and this widget's name, returns the value
        of this widget. ``files`` may contain data coming from
        :attr:`request.FILES <django.http.HttpRequest.FILES>`. Returns ``None``
        if a value wasn't provided. Note also that ``value_from_datadict`` may
        be called more than once during handling of form data, so if you
        customize it and add expensive processing, you should implement some
        caching mechanism yourself.

    .. method:: value_omitted_from_data(data, files, name)

        Given ``data`` and ``files`` dictionaries and this widget's name,
        returns whether or not there's data or files for the widget.

        The method's result affects whether or not a field in a model form
        :ref:`falls back to its default <topics-modelform-save>`.

        Special cases are :class:`~django.forms.CheckboxInput`,
        :class:`~django.forms.CheckboxSelectMultiple`, and
        :class:`~django.forms.SelectMultiple`, which always return
        ``False`` because an unchecked checkbox and unselected
        ``<select multiple>`` don't appear in the data of an HTML form
        submission, so it's unknown whether or not the user submitted a value.

    .. method:: use_required_attribute(initial)

        Given a form field's ``initial`` value, returns whether or not the
        widget can be rendered with the ``required`` HTML attribute. Forms use
        this method along with :attr:`Field.required
        <django.forms.Field.required>` and :attr:`Form.use_required_attribute
        <django.forms.Form.use_required_attribute>` to determine whether or not
        to display the ``required`` attribute for each field.

        By default, returns ``False`` for hidden widgets and ``True``
        otherwise. Special cases are :class:`~django.forms.FileInput` and
        :class:`~django.forms.ClearableFileInput`, which return ``False`` when
        ``initial`` is set, and :class:`~django.forms.CheckboxSelectMultiple`,
        which always returns ``False`` because browser validation would require
        all checkboxes to be checked instead of at least one.

        Override this method in custom widgets that aren't compatible with
        browser validation. For example, a WSYSIWG text editor widget backed by
        a hidden ``textarea`` element may want to always return ``False`` to
        avoid browser validation on the hidden field.

        .. versionchanged:: 3.1

            In older versions, ``True`` was returned for
            :class:`~django.forms.FileInput` when ``initial`` was set.

``MultiWidget``
---------------

.. class:: MultiWidget(widgets, attrs=None)

    A widget that is composed of multiple widgets.
    :class:`~django.forms.MultiWidget` works hand in hand with the
    :class:`~django.forms.MultiValueField`.

    :class:`MultiWidget` has one required argument:

    .. attribute:: MultiWidget.widgets

        An iterable containing the widgets needed. For example::

            >>> from django.forms import MultiWidget, TextInput
            >>> widget = MultiWidget(widgets=[TextInput, TextInput])
            >>> widget.render('name', ['john', 'paul'])
            '<input type="text" name="name_0" value="john"><input type="text" name="name_1" value="paul">'

        You may provide a dictionary in order to specify custom suffixes for
        the ``name`` attribute on each subwidget. In this case, for each
        ``(key, widget)`` pair, the key will be appended to the ``name`` of the
        widget in order to generate the attribute value. You may provide the
        empty string (`''`) for a single key, in order to suppress the suffix
        for one widget. For example::

            >>> widget = MultiWidget(widgets={'': TextInput, 'last': TextInput})
            >>> widget.render('name', ['john', 'lennon'])
            '<input type="text" name="name" value="john"><input type="text" name="name_last" value="paul">'

        .. versionchanged::3.1

            Support for using a dictionary was added.

    And one required method:

    .. method:: decompress(value)

        This method takes a single "compressed" value from the field and
        returns a list of "decompressed" values. The input value can be
        assumed valid, but not necessarily non-empty.

        This method **must be implemented** by the subclass, and since the
        value may be empty, the implementation must be defensive.

        The rationale behind "decompression" is that it is necessary to "split"
        the combined value of the form field into the values for each widget.

        An example of this is how :class:`SplitDateTimeWidget` turns a
        :class:`~datetime.datetime` value into a list with date and time split
        into two separate values::

            from django.forms import MultiWidget

            class SplitDateTimeWidget(MultiWidget):

                # ...

                def decompress(self, value):
                    if value:
                        return [value.date(), value.time()]
                    return [None, None]

        .. tip::

            Note that :class:`~django.forms.MultiValueField` has a
            complementary method :meth:`~django.forms.MultiValueField.compress`
            with the opposite responsibility - to combine cleaned values of
            all member fields into one.

    It provides some custom context:

    .. method:: get_context(name, value, attrs)

        In addition to the ``'widget'`` key described in
        :meth:`Widget.get_context`, ``MultiValueWidget`` adds a
        ``widget['subwidgets']`` key.

        These can be looped over in the widget template:

        .. code-block:: html+django

            {% for subwidget in widget.subwidgets %}
                {% include subwidget.template_name with widget=subwidget %}
            {% endfor %}

    Here's an example widget which subclasses :class:`MultiWidget` to display
    a date with the day, month, and year in different select boxes. This widget
    is intended to be used with a :class:`~django.forms.DateField` rather than
    a :class:`~django.forms.MultiValueField`, thus we have implemented
    :meth:`~Widget.value_from_datadict`::

        from datetime import date
        from django import forms

        class DateSelectorWidget(forms.MultiWidget):
            def __init__(self, attrs=None):
                days = [(day, day) for day in range(1, 32)]
                months = [(month, month) for month in range(1, 13)]
                years = [(year, year) for year in [2018, 2019, 2020]]
                widgets = [
                    forms.Select(attrs=attrs, choices=days),
                    forms.Select(attrs=attrs, choices=months),
                    forms.Select(attrs=attrs, choices=years),
                ]
                super().__init__(widgets, attrs)

            def decompress(self, value):
                if isinstance(value, date):
                    return [value.day, value.month, value.year]
                elif isinstance(value, str):
                    year, month, day = value.split('-')
                    return [day, month, year]
                return [None, None, None]

            def value_from_datadict(self, data, files, name):
                day, month, year = super().value_from_datadict(data, files, name)
                # DateField expects a single string that it can parse into a date.
                return '{}-{}-{}'.format(year, month, day)

    The constructor creates several :class:`Select` widgets in a list. The
    ``super()`` method uses this list to setup the widget.

    The required method :meth:`~MultiWidget.decompress` breaks up a
    ``datetime.date`` value into the day, month, and year values corresponding
    to each widget. If an invalid date was selected, such as the non-existent
    30th February, the :class:`~django.forms.DateField` passes this method a
    string instead, so that needs parsing. The final ``return`` handles when
    ``value`` is ``None``, meaning we don't have any defaults for our
    subwidgets.

    The default implementation of :meth:`~Widget.value_from_datadict` returns a
    list of values corresponding to each ``Widget``. This is appropriate when
    using a ``MultiWidget`` with a :class:`~django.forms.MultiValueField`. But
    since we want to use this widget with a :class:`~django.forms.DateField`,
    which takes a single value, we have overridden this method. The
    implementation here combines the data from the subwidgets into a string in
    the format that :class:`~django.forms.DateField` expects.

.. _built-in widgets:

Built-in widgets
================

Django provides a representation of all the basic HTML widgets, plus some
commonly used groups of widgets in the ``django.forms.widgets`` module,
including :ref:`the input of text <text-widgets>`, :ref:`various checkboxes
and selectors <selector-widgets>`, :ref:`uploading files <file-upload-widgets>`,
and :ref:`handling of multi-valued input <composite-widgets>`.

.. _text-widgets:

Widgets handling input of text
------------------------------

These widgets make use of the HTML elements ``input`` and ``textarea``.

``TextInput``
~~~~~~~~~~~~~

.. class:: TextInput

    * ``input_type``: ``'text'``
    * ``template_name``: ``'django/forms/widgets/text.html'``
    * Renders as: ``<input type="text" ...>``

``NumberInput``
~~~~~~~~~~~~~~~

.. class:: NumberInput

    * ``input_type``: ``'number'``
    * ``template_name``: ``'django/forms/widgets/number.html'``
    * Renders as: ``<input type="number" ...>``

    Beware that not all browsers support entering localized numbers in
    ``number`` input types. Django itself avoids using them for fields having
    their :attr:`~django.forms.Field.localize` property set to ``True``.

``EmailInput``
~~~~~~~~~~~~~~

.. class:: EmailInput

    * ``input_type``: ``'email'``
    * ``template_name``: ``'django/forms/widgets/email.html'``
    * Renders as: ``<input type="email" ...>``

``URLInput``
~~~~~~~~~~~~

.. class:: URLInput

    * ``input_type``: ``'url'``
    * ``template_name``: ``'django/forms/widgets/url.html'``
    * Renders as: ``<input type="url" ...>``

``PasswordInput``
~~~~~~~~~~~~~~~~~

.. class:: PasswordInput

    * ``input_type``: ``'password'``
    * ``template_name``: ``'django/forms/widgets/password.html'``
    * Renders as: ``<input type="password" ...>``

    Takes one optional argument:

    .. attribute:: PasswordInput.render_value

        Determines whether the widget will have a value filled in when the
        form is re-displayed after a validation error (default is ``False``).

``HiddenInput``
~~~~~~~~~~~~~~~

.. class:: HiddenInput

    * ``input_type``: ``'hidden'``
    * ``template_name``: ``'django/forms/widgets/hidden.html'``
    * Renders as: ``<input type="hidden" ...>``

    Note that there also is a :class:`MultipleHiddenInput` widget that
    encapsulates a set of hidden input elements.

``DateInput``
~~~~~~~~~~~~~

.. class:: DateInput

    * ``input_type``: ``'text'``
    * ``template_name``: ``'django/forms/widgets/date.html'``
    * Renders as: ``<input type="text" ...>``

    Takes same arguments as :class:`TextInput`, with one more optional argument:

    .. attribute:: DateInput.format

        The format in which this field's initial value will be displayed.

    If no ``format`` argument is provided, the default format is the first
    format found in :setting:`DATE_INPUT_FORMATS` and respects
    :doc:`/topics/i18n/formatting`.

``DateTimeInput``
~~~~~~~~~~~~~~~~~

.. class:: DateTimeInput

    * ``input_type``: ``'text'``
    * ``template_name``: ``'django/forms/widgets/datetime.html'``
    * Renders as: ``<input type="text" ...>``

    Takes same arguments as :class:`TextInput`, with one more optional argument:

    .. attribute:: DateTimeInput.format

        The format in which this field's initial value will be displayed.

    If no ``format`` argument is provided, the default format is the first
    format found in :setting:`DATETIME_INPUT_FORMATS` and respects
    :doc:`/topics/i18n/formatting`.

    By default, the microseconds part of the time value is always set to ``0``.
    If microseconds are required, use a subclass with the
    :attr:`~Widget.supports_microseconds` attribute set to ``True``.

``TimeInput``
~~~~~~~~~~~~~

.. class:: TimeInput

    * ``input_type``: ``'text'``
    * ``template_name``: ``'django/forms/widgets/time.html'``
    * Renders as: ``<input type="text" ...>``

    Takes same arguments as :class:`TextInput`, with one more optional argument:

    .. attribute:: TimeInput.format

        The format in which this field's initial value will be displayed.

    If no ``format`` argument is provided, the default format is the first
    format found in :setting:`TIME_INPUT_FORMATS` and respects
    :doc:`/topics/i18n/formatting`.

    For the treatment of microseconds, see :class:`DateTimeInput`.

``Textarea``
~~~~~~~~~~~~

.. class:: Textarea

    * ``template_name``: ``'django/forms/widgets/textarea.html'``
    * Renders as: ``<textarea>...</textarea>``

.. _selector-widgets:

Selector and checkbox widgets
-----------------------------

These widgets make use of the HTML elements ``<select>``,
``<input type="checkbox">``, and ``<input type="radio">``.

Widgets that render multiple choices have an ``option_template_name`` attribute
that specifies the template used to render each choice. For example, for the
:class:`Select` widget, ``select_option.html`` renders the ``<option>`` for a
``<select>``.

``CheckboxInput``
~~~~~~~~~~~~~~~~~

.. class:: CheckboxInput

    * ``input_type``: ``'checkbox'``
    * ``template_name``: ``'django/forms/widgets/checkbox.html'``
    * Renders as: ``<input type="checkbox" ...>``

    Takes one optional argument:

    .. attribute:: CheckboxInput.check_test

        A callable that takes the value of the ``CheckboxInput`` and returns
        ``True`` if the checkbox should be checked for that value.

``Select``
~~~~~~~~~~

.. class:: Select

    * ``template_name``: ``'django/forms/widgets/select.html'``
    * ``option_template_name``: ``'django/forms/widgets/select_option.html'``
    * Renders as: ``<select><option ...>...</select>``

    .. attribute:: Select.choices

        This attribute is optional when the form field does not have a
        ``choices`` attribute. If it does, it will override anything you set
        here when the attribute is updated on the :class:`Field`.

``NullBooleanSelect``
~~~~~~~~~~~~~~~~~~~~~

.. class:: NullBooleanSelect

    * ``template_name``: ``'django/forms/widgets/select.html'``
    * ``option_template_name``: ``'django/forms/widgets/select_option.html'``

    Select widget with options 'Unknown', 'Yes' and 'No'

``SelectMultiple``
~~~~~~~~~~~~~~~~~~

.. class:: SelectMultiple

    * ``template_name``: ``'django/forms/widgets/select.html'``
    * ``option_template_name``: ``'django/forms/widgets/select_option.html'``

    Similar to :class:`Select`, but allows multiple selection:
    ``<select multiple>...</select>``

``RadioSelect``
~~~~~~~~~~~~~~~

.. class:: RadioSelect

    * ``template_name``: ``'django/forms/widgets/radio.html'``
    * ``option_template_name``: ``'django/forms/widgets/radio_option.html'``

    Similar to :class:`Select`, but rendered as a list of radio buttons within
    ``<li>`` tags:

    .. code-block:: html

        <ul>
          <li><input type="radio" name="..."></li>
          ...
        </ul>

    For more granular control over the generated markup, you can loop over the
    radio buttons in the template. Assuming a form ``myform`` with a field
    ``beatles`` that uses a ``RadioSelect`` as its widget:

    .. code-block:: html+django

        {% for radio in myform.beatles %}
        <div class="myradio">
            {{ radio }}
        </div>
        {% endfor %}

    This would generate the following HTML:

    .. code-block:: html

        <div class="myradio">
            <label for="id_beatles_0"><input id="id_beatles_0" name="beatles" type="radio" value="john" required> John</label>
        </div>
        <div class="myradio">
            <label for="id_beatles_1"><input id="id_beatles_1" name="beatles" type="radio" value="paul" required> Paul</label>
        </div>
        <div class="myradio">
            <label for="id_beatles_2"><input id="id_beatles_2" name="beatles" type="radio" value="george" required> George</label>
        </div>
        <div class="myradio">
            <label for="id_beatles_3"><input id="id_beatles_3" name="beatles" type="radio" value="ringo" required> Ringo</label>
        </div>

    That included the ``<label>`` tags. To get more granular, you can use each
    radio button's ``tag``, ``choice_label`` and ``id_for_label`` attributes.
    For example, this template...

    .. code-block:: html+django

        {% for radio in myform.beatles %}
            <label for="{{ radio.id_for_label }}">
                {{ radio.choice_label }}
                <span class="radio">{{ radio.tag }}</span>
            </label>
        {% endfor %}

    ...will result in the following HTML:

    .. code-block:: html

        <label for="id_beatles_0">
            John
            <span class="radio"><input id="id_beatles_0" name="beatles" type="radio" value="john" required></span>
        </label>

        <label for="id_beatles_1">
            Paul
            <span class="radio"><input id="id_beatles_1" name="beatles" type="radio" value="paul" required></span>
        </label>

        <label for="id_beatles_2">
            George
            <span class="radio"><input id="id_beatles_2" name="beatles" type="radio" value="george" required></span>
        </label>

        <label for="id_beatles_3">
            Ringo
            <span class="radio"><input id="id_beatles_3" name="beatles" type="radio" value="ringo" required></span>
        </label>

    If you decide not to loop over the radio buttons -- e.g., if your template
    includes ``{{ myform.beatles }}`` -- they'll be output in a ``<ul>`` with
    ``<li>`` tags, as above.

    The outer ``<ul>`` container receives the ``id`` attribute of the widget,
    if defined, or :attr:`BoundField.auto_id` otherwise.

    When looping over the radio buttons, the ``label`` and ``input`` tags include
    ``for`` and ``id`` attributes, respectively. Each radio button has an
    ``id_for_label`` attribute to output the element's ID.

``CheckboxSelectMultiple``
~~~~~~~~~~~~~~~~~~~~~~~~~~

.. class:: CheckboxSelectMultiple

    * ``template_name``: ``'django/forms/widgets/checkbox_select.html'``
    * ``option_template_name``: ``'django/forms/widgets/checkbox_option.html'``

    Similar to :class:`SelectMultiple`, but rendered as a list of checkboxes:

    .. code-block:: html

        <ul>
          <li><input type="checkbox" name="..." ></li>
          ...
        </ul>

    The outer ``<ul>`` container receives the ``id`` attribute of the widget,
    if defined, or :attr:`BoundField.auto_id` otherwise.

Like :class:`RadioSelect`, you can loop over the individual checkboxes for the
widget's choices. Unlike :class:`RadioSelect`, the checkboxes won't include the
``required`` HTML attribute if the field is required because browser validation
would require all checkboxes to be checked instead of at least one.

When looping over the checkboxes, the ``label`` and ``input`` tags include
``for`` and ``id`` attributes, respectively. Each checkbox has an
``id_for_label`` attribute to output the element's ID.

.. _file-upload-widgets:

File upload widgets
-------------------

``FileInput``
~~~~~~~~~~~~~

.. class:: FileInput

    * ``template_name``: ``'django/forms/widgets/file.html'``
    * Renders as: ``<input type="file" ...>``

``ClearableFileInput``
~~~~~~~~~~~~~~~~~~~~~~

.. class:: ClearableFileInput

    * ``template_name``: ``'django/forms/widgets/clearable_file_input.html'``
    * Renders as: ``<input type="file" ...>`` with an additional checkbox
      input to clear the field's value, if the field is not required and has
      initial data.

.. _composite-widgets:

Composite widgets
-----------------

``MultipleHiddenInput``
~~~~~~~~~~~~~~~~~~~~~~~

.. class:: MultipleHiddenInput

    * ``template_name``: ``'django/forms/widgets/multiple_hidden.html'``
    * Renders as: multiple ``<input type="hidden" ...>`` tags

    A widget that handles multiple hidden widgets for fields that have a list
    of values.

``SplitDateTimeWidget``
~~~~~~~~~~~~~~~~~~~~~~~

.. class:: SplitDateTimeWidget

    * ``template_name``: ``'django/forms/widgets/splitdatetime.html'``

    Wrapper (using :class:`MultiWidget`) around two widgets: :class:`DateInput`
    for the date, and :class:`TimeInput` for the time. Must be used with
    :class:`SplitDateTimeField` rather than :class:`DateTimeField`.

    ``SplitDateTimeWidget`` has several optional arguments:

    .. attribute:: SplitDateTimeWidget.date_format

        Similar to :attr:`DateInput.format`

    .. attribute:: SplitDateTimeWidget.time_format

        Similar to :attr:`TimeInput.format`

    .. attribute:: SplitDateTimeWidget.date_attrs
    .. attribute:: SplitDateTimeWidget.time_attrs

        Similar to :attr:`Widget.attrs`. A dictionary containing HTML
        attributes to be set on the rendered :class:`DateInput` and
        :class:`TimeInput` widgets, respectively. If these attributes aren't
        set, :attr:`Widget.attrs` is used instead.

``SplitHiddenDateTimeWidget``
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

.. class:: SplitHiddenDateTimeWidget

    * ``template_name``: ``'django/forms/widgets/splithiddendatetime.html'``

    Similar to :class:`SplitDateTimeWidget`, but uses :class:`HiddenInput` for
    both date and time.

``SelectDateWidget``
~~~~~~~~~~~~~~~~~~~~

.. class:: SelectDateWidget

    * ``template_name``: ``'django/forms/widgets/select_date.html'``

    Wrapper around three :class:`~django.forms.Select` widgets: one each for
    month, day, and year.

    Takes several optional arguments:

    .. attribute:: SelectDateWidget.years

        An optional list/tuple of years to use in the "year" select box.
        The default is a list containing the current year and the next 9 years.

    .. attribute:: SelectDateWidget.months

        An optional dict of months to use in the "months" select box.

        The keys of the dict correspond to the month number (1-indexed) and
        the values are the displayed months::

            MONTHS = {
                1:_('jan'), 2:_('feb'), 3:_('mar'), 4:_('apr'),
                5:_('may'), 6:_('jun'), 7:_('jul'), 8:_('aug'),
                9:_('sep'), 10:_('oct'), 11:_('nov'), 12:_('dec')
            }

    .. attribute:: SelectDateWidget.empty_label

        If the :class:`~django.forms.DateField` is not required,
        :class:`SelectDateWidget` will have an empty choice at the top of the
        list (which is ``---`` by default). You can change the text of this
        label with the ``empty_label`` attribute. ``empty_label`` can be a
        ``string``, ``list``, or ``tuple``. When a string is used, all select
        boxes will each have an empty choice with this label. If ``empty_label``
        is a ``list`` or ``tuple`` of 3 string elements, the select boxes will
        have their own custom label. The labels should be in this order
        ``('year_label', 'month_label', 'day_label')``.

        .. code-block:: python

            # A custom empty label with string
            field1 = forms.DateField(widget=SelectDateWidget(empty_label="Nothing"))

            # A custom empty label with tuple
            field1 = forms.DateField(
                widget=SelectDateWidget(
                    empty_label=("Choose Year", "Choose Month", "Choose Day"),
                ),
            )