symfony form allow_add
// add-collection-widget.js
jQuery(document).ready(function () {
jQuery('.add-another-collection-widget').click(function (e) {
var list = jQuery(jQuery(this).attr('data-list-selector'));
// Try to find the counter of the list or use the length of the list
var counter = list.data('widget-counter') || list.children().length;
// grab the prototype template
var newWidget = list.attr('data-prototype');
// replace the "__name__" used in the id and name of the prototype
// with a number that's unique to your emails
// end name attribute looks like name="contact[emails][2]"
newWidget = newWidget.replace(/__name__/g, counter);
// Increase the counter
counter++;
// And store it, the length cannot be used if deleting widgets is allowed
list.data('widget-counter', counter);
// create a new list element and add it to the list
var newElem = jQuery(list.attr('data-widget-tags')).html(newWidget);
newElem.appendTo(list);
});
});