Remove the “choices” part in the category field. By having it “choices=[(”, ”), ]”, you are requiring the choice to be blank. Any value would fail. If you remove, like below, any value will be accepted (assuming it’s under 20 characters).

    category = models.CharField(max_length=20)

I have a Model and a ModelForm. The ModelForm has a dependent dropdown list implemented with JQuery. The category dropdown changes accordingly each time a choice from the gender dropdown is selected (Done with JQuery). Whenever I try to save the ModelForm in my views, I get an error saying that the choice that I have selected is not valid. Does it have to do with the choices/options to the category dropdown being added after a choice from the gender dropdown has been selected? Does it cause some conflict with the default empty two-tuple of the category field? The errors occur on the category field.

In models.py,

GENDER_CHOICES = [
    ('Male', 'Male'),
    ('Female', 'Female'),
]

class Person(models.Model):
    name = models.CharField(max_length=50, unique=True)
    gender = models.CharField(max_length=7, choices=GENDER_CHOICES)
    category = models.CharField(max_length=20, choices=[('', ''), ])

In forms.py,

class PersonForm(ModelForm):

    class Meta:
        model = Person

        fields = [

            'name',
            'gender',
            'category',

        ]

In views.py,

def personform_page(request):

    context = {}

    if request.method == 'POST':
        personform = PersonForm(request.POST)

        if personform.is_valid():
            personform.save()
            return redirect('personform_page')

        context['personform'] = personform

    else:
        personform = PersonForm()
        context['personform'] = personform

    context['male_categories'] = MALE_CATEGORIES
    context['female_categories'] = FEMALE_CATEGORIES

    return render(request, 'app1/personform_page.html', context=context)

In app1/personform_page.html,

<form class="form-class" action="" method="post" enctype="multipart/form-data">
    {% csrf_token %}
    {% for field in personform %}

        <p>
            {{ field.label_tag }}
            {{ field }}

            {% if field.help_text %}

                <small style="color: black;"> {{ field.help_text }} </small>

            {% endif %}

            {% for error in field.errors %}

                <p style="color: red;"> {{ error }} </p>

            {% endfor %}

        </p>

    {% endfor %}

    <button class="btn btn-outline-primary" type="submit">Join</button>

</form>

<script>

    $(document).ready( function() {

        $("#id_category").hide();

        $("#id_gender").on('change', function(){

            var gender = $("#id_gender").val();

            if(gender == 'Male'){

                $('#id_category').empty();
                $("#id_category").show();

                var maleCategories = ['Male Category 1', 'Male Category 2', 'Male Category 3'];
                var length = maleCategories.length;

                var i;
                for(i=0; i < length; i++){
                    maleCategory = maleCategories[i];
                    $('#id_category').append(

                        `
                        <option value="${maleCategory}">
                            ${maleCategory}
                        </option>
                        `

                    );
                }

            }
            else if(gender == 'Female'){

                $('#id_category').empty();
                $("#id_category").show();

                var femaleCategories = ['Female Category 1', 'Female Category 2', 'Female Category 3'];
                var length = femaleCategories.length;

                var i;
                for(i=0; i < length; i++){
                    femaleCategory = femaleCategories[i];
                    $('#id_category').append(

                        `
                        <option value="${femaleCategory}">
                            ${femaleCategory}
                        </option>
                        `

                    );
                }

            }
            else{

                $('#id_category').empty();

            }

        });

    });

</script>