gistfile1.js

    jQuery('a.add-question').live('click', function(e) {
      e.stopPropagation()
      e.preventDefault()

      var form_el = jQuery(this).parents('form')
      var num_questions = form_el.find('.question').length
      var new_question_el = form_el.find('.question:last').clone()
      new_question_el.appendTo('.questions',form_el).hide().slideDown("fast")
      new_question_el.find('label,select,input,textarea').each(function(e) {
        var el = jQuery(this)
        _.each([ 'class', 'id', 'for','name' ], function(attr_name) {
          var attr_val = el.attr(attr_name)
          if(attr_val) {
            attr_val = attr_val.replace( /_\d+_/, "_"+total_qus+"_" )
            attr_val = attr_val.replace( /\[\d+\]/, "["+total_qus+"]" )
            el.attr( attr_name, attr_val )
          }
        })
      })

$('body').on('click', 'a.add-new-field', function(e) {
  var self = $(this)
    , tmpl = self.data('template');

  if (tmpl) {
    var newField = $(tmpl).clone();
    self.remove();

    newField.find('label,select,input,textarea').each(function() {
      var el = $(this), num;
      _.each(['class', 'id', 'for', 'name'], function(attr) {
        var val;
        if (val = el.attr(attr)) {
          if (!num) {
            num = val.match(/(_\d+)|(\[\d+\])/)[0];
            num = num.replace(/\_|\[|\]/, '');
            num = parseInt(num, 10) + 1;
          }
          val = val.replace(/_\d+/, '_' +num);
          val = val.replace(/\[\d+\]/, '[' +num+ ']');
          el.attr(attr, val);
          $(tmpl).parent().append(newField);
        }
      });
    });
  }
});