function merge_parameter_and_refresh(key, value) {
  key = escape(key); value = escape(value);
  var kvp = document.location.search.substr(1).split('&');
  if (kvp == '') {
    document.location.search = '?' + key + '=' + value;
  }
  else {
    var i = kvp.length; var x; while (i--) {
      x = kvp[i].split('=');
      if (x[0] == key) {
        x[1] = value;
        kvp[i] = x.join('=');
        break;
      }   
    }   
    if (i < 0) { kvp[kvp.length] = [key, value].join('='); }
    //this will reload the page, it's likely better to store this until finished
    document.location.search = kvp.join('&');
  }
}

<script>
  $('#good_goods_first_category_id').change(function(){
    merge_parameter_and_refresh('category_id', $(this).val())
  })
</script>

//= require sortable-rails-jquery
//= require_tree .

<tbody id="steps_sortable_table">
    <% @steps.each do |step| %>
      <tr data-id = '<%= step.id%>'>
      .......
      </tr>
    <% end %>
  </tbody>

<script>
  $(' #steps_sortable_table' ).sortable({
        opacity: 0.6,
        revert: true,
        cursor: 'move',
        onUpdate: function(evt) {
            neworder = new Array();
            $('#steps_sortable_table').children().each(function() {
                id = $(this).attr("data-id");
                neworder.push({
                    id: id
                });
            });
            $.ajax({
                url: "/steps/sort",
                type: "POST",
                data: {
                    steps: JSON.stringify(neworder)
                }
            });
            console.log(neworder);
        }
    });
</script>

def sort
  if params[:steps].present?
    JSON.parse(params[:steps]).each_with_index do |x, index|
      idx = x["id"]
      position = index+1
      step = Step.find(idx)
      step.update_attribute("position", position)
    end
  end
  render nothing: true
end

resources :users