example.html

<ul data-collection-item-prototype="prototype goes here">
    <li>
        <label for="name">Name</label>
        <input type="text" id="name" name="name">
    </li>
    <li>
        <label for="email">Email</label>
        <input type="email" id="email" name="email">
    </li>
    <li>
        <ul class="js-collection-type" data-collection-prototype="">
            <li class="js-collection-item">
                <label for="book1">Book 1</label>
                <input type="text" id="book1" name="books[1]">
                <a href="#" class="js-collection-remove">Remove Book</a>
            </li>
            <li class="js-collection-placeholder">
                <a href="#" class="js-collection-add">+ Add Book</a>
            </li>
        </ul>
    </li>
    <li>
        <input type="submit" class="btn" value="Register">
    </li>
</ul>

FormCollectionView.js

/**
 * @fileOverview Form collection handler
 * 
 * @author Matthew Loberg
 */
define(function(require, module, exports) {
    'use strict';

    var $ = require('jquery');

    /**
     * FormCollectionView to handle form collections
     *
     * @class FormCollectionView
     * @constructor
     */
    var FormCollectionView = function() {
        this.init();
    };

    /**
     * Initializes the UI Component View
     *
     * @method init
     * @chainable
     */
    FormCollectionView.prototype.init = function() {
        var self = this;

        $('.js-collection-type').not('.js-collection-type_initialized').each(function() {
            var $element = $(this);

            self.setup($element);
        }).addClass('js-collection-type_initialized');

        return this;
    };

    /**
     * Setup form collection element
     *
     * @method setup
     * @param {jQuery} $collectionContainer collection element
     * @chainable
     */
    FormCollectionView.prototype.setup = function($collectionContainer) {
        $collectionContainer.data('index', $collectionContainer.find('.js-collection-item').length);

        this.setupRemove($collectionContainer)
            .setupAdd($collectionContainer);
    };

    /**
     * Setup item remove
     *
     * @method setupRemove
     * @param {jQuery} $collectionContainer collection element
     * @chainable
     */
    FormCollectionView.prototype.setupRemove = function($collectionContainer) {
        var self = this;

        $collectionContainer.find('.js-collection-item').not('.js-collection-item_initialized').each(function() {
            var $element = $(this);
            self.itemRemoveHandler($element);
        }).addClass('js-collection-item_initialized');

        return this;
    };

    /**
     * Setup item add
     *
     * @method setupAdd
     * @param {jQuery} $collectionContainer collection element
     */
    FormCollectionView.prototype.setupAdd = function($collectionContainer) {
        var self = this;
        var $addLink = $collectionContainer.find('.js-collection-add');

        if ($addLink) {
            $addLink.on('click', function(e) {
                e.preventDefault();

                self.itemAddHandler($collectionContainer);
            });
        }
    };

    /**
     * Setup remove handler on item
     *
     * @method itemRemoveHandler
     * @param {jQuery} $element collection item
     */
    FormCollectionView.prototype.itemRemoveHandler = function($element) {
        var $removeLink = $element.find('.js-collection-remove');

        if ($removeLink) {
            $removeLink.on('click', function(e) {
                e.preventDefault();

                $element.remove();
            });
        }
    };

    /**
     * Setup add handler for item
     *
     * @method itemAddHandler
     * @param {jQuery} $collectionContainer collection container
     */
    FormCollectionView.prototype.itemAddHandler = function($collectionContainer) {
        var prototype = $collectionContainer.data('collection-item-prototype');
        var index = $collectionContainer.data('index') + 1;
        var newInput = prototype.replace(/__name__/g, index);

        $collectionContainer.data('index', index);

        $collectionContainer.find('.js-collection-placeholder').before(newInput);

        this.setupRemove($collectionContainer);
    };

    return FormCollectionView;
});