I\'m building a form where I need multiple optional inputs, what I have is basically this:
Every time a user presses the plus button a new row of form inputs
Building on the other answers, I simplified things a bit. By cloning the last element, we get the "add new" button for free (you have to change the ID to a class because of the cloning) and also reduce DOM operations. I had to use filter() instead of find() to get only the last element.
$('.js-addNew').on('click', function(e) {
e.preventDefault();
var $rows = $('.person'),
$last = $rows.filter(':last'),
$newRow = $last.clone().insertAfter($last);
$last.find($('.js-addNew')).remove(); // remove old button
$newRow.hide().find('input').val('');
$newRow.slideDown(500);
});