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 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 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 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 attrs. See BoundField.id_for_label for an example.

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 define a “Media” inner class or create a “media” property.

These methods involve somewhat advanced Python programming and are described in detail in the Form Assets topic guide.

Widget¶

class Widget(attrs=None)[source]¶

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

attrs¶

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

>>> 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">'

supports_microseconds¶

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

format_value(value)[source]¶

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.

get_context(name, value, attrs)[source]¶

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 format_value().

• 'attrs': HTML attributes to be set on the rendered widget. The combination of the 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.

id_for_label(id_)[source]¶

Returns the HTML ID attribute of this widget for use by a <label>, given the ID of the field. Returns an empty string 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.

render(name, value, attrs=None, renderer=None)[source]¶

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

value_from_datadict(data, files, name)[source]¶

Given a dictionary of data and this widget’s name, returns the value of this widget. files may contain data coming from request.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.

value_omitted_from_data(data, files, name)[source]¶

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 falls back to its default.

Special cases are CheckboxInput, CheckboxSelectMultiple, and 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.

use_fieldset¶

New in Django 4.1.

An attribute to identify if the widget should be grouped in a <fieldset> with a <legend> when rendered. Defaults to False but is True when the widget contains multiple <input> tags such as CheckboxSelectMultiple, RadioSelect, MultiWidget, SplitDateTimeWidget, and SelectDateWidget.

use_required_attribute(initial)[source]¶

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 Field.required and 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 FileInput and ClearableFileInput, which return False when initial is set, and 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.

MultiWidget¶

class MultiWidget(widgets, attrs=None)[source]¶

A widget that is composed of multiple widgets. MultiWidget works hand in hand with the MultiValueField.

MultiWidget has one required argument:

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", "paul"])
'<input type="text" name="name" value="john"><input type="text" name="name_last" value="paul">'

And one required method:

decompress(value)[source]¶

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 SplitDateTimeWidget turns a 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 MultiValueField has a complementary method compress() with the opposite responsibility - to combine cleaned values of all member fields into one.

It provides some custom context:

get_context(name, value, attrs)[source]¶

In addition to the 'widget' key described in Widget.get_context(), MultiWidget adds a widget['subwidgets'] key.

These can be looped over in the widget template:

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

Here’s an example widget which subclasses MultiWidget to display a date with the day, month, and year in different select boxes. This widget is intended to be used with a DateField rather than a MultiValueField, thus we have implemented 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 Select widgets in a list. The super() method uses this list to set up the widget.

The required method 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 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 value_from_datadict() returns a list of values corresponding to each Widget. This is appropriate when using a MultiWidget with a MultiValueField. But since we want to use this widget with a 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 DateField expects.

Widgets handling input of text¶

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

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 Select widget, select_option.html renders the <option> for a <select>.

File upload widgets¶

Composite widgets¶