Ticket 16304 -- Add HTML5 placeholder attribute support to form fields

django/forms/fields.py

@@ -20,7 +20,7 @@
 from django.core.exceptions import ValidationError
 from django.forms.util import ErrorList, from_current_timezone, to_current_timezone
 from django.forms.widgets import (
-    TextInput, NumberInput, EmailInput, URLInput, HiddenInput,
+    Input, Textarea, TextInput, NumberInput, EmailInput, URLInput, HiddenInput,
     MultipleHiddenInput, ClearableFileInput, CheckboxInput, Select,
     NullBooleanSelect, SelectMultiple, DateInput, DateTimeInput, TimeInput,
     SplitDateTimeWidget, SplitHiddenDateTimeWidget, FILE_INPUT_CONTRADICTION
@@ -199,8 +199,10 @@ def __deepcopy__(self, memo):
         return result
 
 class CharField(Field):
-    def __init__(self, max_length=None, min_length=None, *args, **kwargs):
-        self.max_length, self.min_length = max_length, min_length
+    def __init__(self, max_length=None, min_length=None, placeholder=None,
+                 *args, **kwargs):
+        self.max_length, self.min_length, self.placeholder = (
+            max_length, min_length, placeholder)
         super(CharField, self).__init__(*args, **kwargs)
         if min_length is not None:
             self.validators.append(validators.MinLengthValidator(min_length))
@@ -218,6 +220,8 @@ def widget_attrs(self, widget):
         if self.max_length is not None and isinstance(widget, TextInput):
             # The HTML attribute is maxlength, not max_length.
             attrs.update({'maxlength': str(self.max_length)})
+        if self.placeholder and isinstance(widget, (Input, Textarea)):
+            attrs.update({'placeholder': self.placeholder})
         return attrs
 
 class IntegerField(Field):

docs/ref/forms/fields.txt

@@ -318,13 +318,15 @@ For each field, we describe the default widget used if you don't specify
       Otherwise, all inputs are valid.
     * Error message keys: ``required``, ``max_length``, ``min_length``
 
-    Has two optional arguments for validation:
+    Has three optional arguments for validation:
 
     .. attribute:: max_length
     .. attribute:: min_length
+    .. attribute:: placeholder
 
-    If provided, these arguments ensure that the string is at most or at least
-    the given length.
+    If provided, max_length and min_length ensure that the string is at most or at least
+    the given length. If provided, placeholder will show a placeholder attribute
+    in the html element, if it's an input box or a textarea.
 
 ``ChoiceField``
 ~~~~~~~~~~~~~~~

tests/forms_tests/tests/test_fields.py

@@ -125,6 +125,16 @@ def test_charfield_5(self):
         self.assertEqual(f.max_length, None)
         self.assertEqual(f.min_length, 10)
 
+    def test_charfield_6(self):
+        f = CharField(placeholder='This is a random placeholder')
+        self.assertEqual('This is a random placeholder', f.placeholder)
+        self.assertEqual('This is a random placeholder', f.widget.attrs['placeholder'])
+
+    def test_charfield_7(self):
+        f = CharField(placeholder='This is another placeholder', widget=Textarea)
+        self.assertEqual('This is another placeholder', f.placeholder)
+        self.assertEqual('This is another placeholder', f.widget.attrs['placeholder'])
+
     def test_charfield_widget_attrs(self):
         """
         Ensure that CharField.widget_attrs() always returns a dictionary.