Executing action with Ajax in RoR, and modifying html without refreshing the page

index.html.erb

...
<tr id="<%= day.id %>">
...
  <td><%= link_to 'Total', total_day_path(day), :remote => true %></td>
...

myaction.js.erb

$("tr#<%= @day.id %> td.oTotal").html("<%= @day.oTotal %>");
$("tr#<%= @day.id %> td.dTotal").html("<%= @day.dTotal %>");

myentity_controller.erb

...
def myaction
  ...
  respond_to do |format|
    format.js {}
  end
end
...

In index.html.erb we produce a link that triggers an ajax action when clicked by means of :remote => true. In this example the entity or model is Day and the action is total.

Notice that we render day.id as id for the html element we want to manipulate. This is how we could identify and work with that specific element (any element in the identified row).

Let's look at myentity_controller.erb. There we got the repond_to block and the condition format.js {}. This indicates that javascript will be sent as response and the correspondent code must be included in a js.erb view with the name of the action (e.g. myaction.js.erb).

In myaction.js.erb we can use JQuery to manipulate the dom and html elements with the powerful help of Rails bindings.