main.js

    $('div.collection div.add a').click(function() {
        var $parent = $(this).parent().parent(), $prototype = $parent.find('div:first div:last'), html;

        html = $prototype.attr('data-prototype').replace(/\$\$name\$\$/g, $parent.find('div:first > div:not(:last)').length);

        $prototype.before(html);
        
        return false;
    });

view.html

        <div class="collection">
            {{ form_row(form.parameters) }}
            <div class="add">
                <a style="float: right;" href="#" title="Add">Add</a>
            </div>
        </div>