How would you make a dynamic formset in Django?

Question

Here's the way I'm doing it:

{{ formset.management_form }}
<table>
    {% for form in formset.forms %}
        {{ form }}
    {% endfor %}
</table>
<a href="javascript:void(0)" id="add_form">Add Form</a>   

And here's the JS:

var form_count = {{formset.total_form_count}};
$('#add_form').click(function() {
    form_count++;
    var form = '{{formset.empty_form|escapejs}}'.replace(/__prefix__/g, form_count);
    $('#forms').append(form)
    $('#id_form-TOTAL_FORMS').val(form_count);
});

What specifically bothers me is that I had to write that escapejs template tag myself. It just strips all newlines and escapes any single quotes so that it doesn't mess up my string. But what exactly did the Django makers expect us to do in this situation? And why do they have this TOTAL_FORMS hidden field, when they could have just used an array like <input name="my_form_field[0]" /> and then counted its length instead?

Answer 1

There are a few places in Django where "the reason why" is because that's how it was implemented for the Django admin app, and I believe this is one of them. Thus the answer is they expect you to implement your own javascript.

See this SO question Dynamically adding a form... for some more javascript ideas.

There are also two pluggable apps available, django-dynamic-formset and django-dinamyc-form which I hadn't seen until just now when looking up the first one.

Answer 2

This question is a bit old, but it took me a while to figure this out as well.

I suggest rendering formset.empty_form in your template as a hidden field, and referencing this field in your javascript.

Here's a complicated dynamic formset example from the django admin site: (but note that it has not been updated to use empty_form....)

[js] http://code.djangoproject.com/browser/django/trunk/django/contrib/admin/media/js/inlines.js

[html template] http://code.djangoproject.com/browser/django/trunk/django/contrib/admin/templates/admin/edit_inline/tabular.html