title: Django - initial checked CheckboxInput
body: <p>I want my CheckboxInput was checked by default :</p>
  
  <p><strong>My models :</strong></p>
  
  <pre><code>class Sub(models.Model):
      user = models.OneToOneField(User)
      batata = models.BooleanField(default=False)
  
  class presentationForm(forms.ModelForm):
      class Meta : 
          model = Sub
      widgets = {
          'batata': forms.CheckboxInput(attrs={'id':'batata'}),
      }
      def __init__(self, *args, **kwargs):
          self.valbata = kwargs.pop("arg_bata")
          super(presentationForm, self).__init__(*args, **kwargs)
          self.fields['batata'].initial = True
  </code></pre>
  
  <p><strong>My view :</strong></p>
  
  <pre><code>def theview(request):
      form = presentationForm(arg_bata="Azerty")
      return render(request,"le_site/page-batata.html",locals())
  </code></pre>
  
  <p><strong>My template :</strong></p>
  
  <pre><code>&lt;div id="mod"&gt;
      {% load bootstrap %}
      &lt;form method="POST" id="formModificationFic"&gt;
              {% csrf_token %}
              {{ form.batata|bootstrap }}
       ...
              &lt;div class="col-md-offset-4 col-md-3"&gt;
                  &lt;input type="submit" id="le_bouton" value="Confirmer"&gt;
              &lt;/div&gt;
        &lt;/form&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p><strong>My JS :</strong> </p>
  
  <pre><code>function envoie_post(){
     var batataRep = document.getElementById("batata").checked;
     alert("batataRep : "+batataRep);  
     $.post("http://localhost:8000/page-batata",  "batataRep":batataRep});
  }
  
  $(document).ready(function() {
          $("#formModificationFic").submit(function() {
          envoie_post();
          return false;
      });
  });
  </code></pre>
  
  <p>But in my page, the checbkoxInput "batata" isn't checked...
  And I think the JS hasn't effects</p>