5.7. Ajax

Be sure to include the JavaScript libraries in the layout:

<%= javascript_include_tag :defaults %>

5.7.1. Linking to Remote Action

<%= link_to_remote "link", :update => 'some_div',
                           :url => { :action => 'show', :id => post.id } %>

<%= link_to_remote "link", :url => { :action => 'create',
                           :update => { :success => 'good_div',
                                        :failure => 'error_div' },
                           :loading => 'Element.show('spinner'),
                           :complete => 'Element.hide('spinner') } %>

5.7.2. Callbacks

:loading

Called when the remote document is being loaded with data by the browser.

:loaded

Called when the browser has finished loading the remote document.

:interactive

Called when the user can interact with the remote document, even though it has not finished loading.

:success

Called when the XMLHttpRequest is completed, and the HTTP status code is in the 2XX range.

:failure

Called when the XMLHttpRequest is completed, and the HTTP status code is not in the 2XX range.

:complete

Called when the XMLHttpRequest is complete (fires after success/failure if they are present).

You can also specify reactions to return codes directly:

link_to_remote word,
    :url => { :action => "action" },
    404 => "alert('Not found...? Wrong URL...?')",
    :failure => "alert('HTTP Error ' + request.status + '!')"

5.7.3. Ajax Forms

You can create a form that will submit via an XMLHttpRequest instead of a POST request. The parameters are passed exactly the same way (so the controller can use the params method to access the parameters). Fallback for non-JavaScript-enabled browsers can be specified by using the :action methods in the :html option:

form_remote_tag :html => { :action => url_for(:controller => 'controller',
                                              :action => 'action'),
                           :method => :post }

5.7.4. Autocompleting Text Field

In the view t\emplate:

<%= text_field_with_auto_complete :model, :attribute %>

In the controller:

auto_complete_for :model, :attribute

5.7.5. Observe Field

<label for="search">Search term:</label>
<%= text_field_tag :search %>
<%= observe_field(:search,
                  :frequency => 0.5,
                  :update => :results,
                  :url => { :action => :search }) %>
<div id="results"></div>

Optionally specify:

:on => :blur    # trigger for event (default :changed or :clicked)
:with => ...    # a JavaScript expression to specify what value is sent
                # defaults to "value"
:with => 'bla'  # "'bla' = value"
:with => 'a=b'  # "a=b"

5.7.6. Observe Form

Same semantics as observe_field.

5.7.7. periodically_call_remote

<%= periodically_call_remote(:update => 'process-list',
                             :url => { :action => :ps },
                             :frequency => 2 ) %>

Learn more: http://api.rubyonrails.com/classes/ActionView/Helpers/JavaScriptHelper.html.