Simple inlineformset plugin for jQuery and Django. This is a work in progress and not ready for a production environment, but a good starting point for forks to add additional functionality.

jquery.inlineformset.js

;(function($){
	
	$.inlineformset = {
		
		defaults: {
			extra: 3,
			formSelector: '.form',
			formsetSelector: '.formset',
			hideOnDeletion: true,
		},
		
	};
	
	$.fn.inlineformset = function(options)
	{
		
		if ($(this).data('inlineformset-instance'))
		{
			return $(this).data('inlineformset-instance');
		}
		else
		{
			
			function InlineFormSet(container, options)
			{
				
				var container = container;
				var settings = $.extend($.inlineformset.defaults, options);
				
				var formset = $(container).find(settings.formsetSelector).get(0);
				var totalForms = $(container).find('input[name$="TOTAL_FORMS"]').get(0);
				var initialForms = $(container).find('input[name$="INITIAL_FORMS"]').get(0);
				var prototypeForm = $(container).find(settings.formSelector + ':last').clone(true);
				
				var initialize = function(self)
				{
					
					$(formset).find(settings.formSelector).each(function(i){
						
						// Delete each form that does not have an ID or parent object associated with it.
						if(!$(this).find('input[name$="-id"]').val() && !$(this).find('input[name$="_ptr"]').val())
						{
							$(this).remove();
						}
						else 
						{
							// Add the deletion handler to the form if necessary.
							if (settings.hideOnDeletion) { 
								addDeletionHandler($(this)); 
							}
						}
						
					});
					
					$(initialForms).val($(formset).find(settings.formSelector).length);
					
					// Add the extra forms as neccessary.
					for (var i = 0; i < settings.extra; i++)
					{
						self.addForm(false);
					}
					
					refreshFormset();
					
				}
				
				var addDeletionHandler = function(form) 
				{
					$(form).find('input[name$="DELETE"]').bind('change', {'settings': settings}, function(event){
						var settings = event.data.settings;
						$(this).closest(settings.formSelector).addClass('deleted').hide();
					});
				}
				
				var getFormset = function() 
				{ 
					return formset; 
				}
				
				var getPrototypeForm = function() 
				{
					var form = $(prototypeForm).clone(true);
					if (settings.hideOnDeletion) { addDeletionHandler(form); }
					return form;
				}
				
				var refreshFormset = function()
				{
					
					var forms = {}
					var fieldname_regex = new RegExp('^([a-zA-Z0-9_-]+)-([0-9]+)-([a-zA-Z0-9_]+)$');
					
					$(container).find(settings.formSelector).each(function(i){
						
						var prefix = null;
						
						$(this).find('input, select').each(function(i){
							var matches = $(this).attr('name').match(fieldname_regex);
							if (matches) 
							{
								prefix = matches[1];
								return false;
							}
						});
						
						if (prefix)
						{
							if (typeof forms[prefix] == "number")
							{
								forms[prefix] = forms[prefix] + 1;
							}
							else
							{
								forms[prefix] = 0;
							}
						}
						
						$(this).find('input, select').each(function(i){
							var matches = $(this).attr('name').match(fieldname_regex);
							if (matches)
							{
								var new_field_name = prefix + '-' + forms[prefix] + '-' + matches[3];
								$(this).attr('id', 'id_' + new_field_name);
								$(this).attr('name', new_field_name);
							}
						});
						
						$(this).find('label').each(function(i){
							var matches = $(this).attr('for').match(fieldname_regex);
							if (matches)
							{
								var new_field_name = prefix + '-' + forms[prefix] + '-' + matches[3];
								$(this).attr('for', 'id_' + new_field_name);
							}
						});
						
					});
					
					$(totalForms).val($(container).find(settings.formSelector).length);
					
				}
				
				this.addForm = function(refresh)
				{
					// Default the value of the refresh argument to "true".
					if (refresh == undefined) { refresh = true; }
					
					form = getPrototypeForm();
					formset = getFormset();
					$(formset).append(form);
					
					if (refresh) { refreshFormset(); }
				};
					
				initialize(this);
				
				return this;
				
			};

			$(this).data('inlineformset-instance', new InlineFormSet(this, options));
			return $(this).data('inlineformset-instance');
			
		}
		
	}
	
})(jQuery);