ActionView::Helpers::PrototypeHelper

Creates a button with an onclick event which calls a remote action via XMLHttpRequest The options for specifying the target with :url and defining callbacks is the same as link_to_remote.

Returns ‘eval(request.responseText)’ which is the JavaScript function that form_remote_tag can call in :complete to evaluate a multiple update return document using update_element_function calls.

Alias for remote_form_for

Returns a form tag that will submit using XMLHttpRequest in the background instead of the regular reloading POST arrangement. Even though it‘s using JavaScript to serialize the form elements, the form submission will work just like a regular submission as viewed by the receiving side (all elements available in params). The options for specifying the target with :url and defining callbacks is the same as link_to_remote.

A "fall-through" target for browsers that doesn‘t do JavaScript can be specified with the :action/:method options on :html.

Example:

  # Generates:
  #      <form action="/some/place" method="post" onsubmit="new Ajax.Request('',
  #      {asynchronous:true, evalScripts:true, parameters:Form.serialize(this)}); return false;">
  form_remote_tag :html => { :action =>
    url_for(:controller => "some", :action => "place") }

The Hash passed to the :html key is equivalent to the options (2nd) argument in the FormTagHelper.form_tag method.

By default the fall-through action is the same as the one specified in the :url (and the default method is :post).

form_remote_tag also takes a block, like form_tag:

  # Generates:
  #     <form action="/" method="post" onsubmit="new Ajax.Request('/',
  #     {asynchronous:true, evalScripts:true, parameters:Form.serialize(this)});
  #     return false;"> <div><input name="commit" type="submit" value="Save" /></div>
  #     </form>
  <% form_remote_tag :url => '/posts' do -%>
    <div><%= submit_tag 'Save' %></div>
  <% end -%>

Returns a link to a remote action defined by options[:url] (using the url_for format) that‘s called in the background using XMLHttpRequest. The result of that request can then be inserted into a DOM object whose id can be specified with options[:update]. Usually, the result would be a partial prepared by the controller with render :partial.

Examples:

  # Generates: <a href="#" onclick="new Ajax.Updater('posts', '/blog/destroy/3', {asynchronous:true, evalScripts:true});
  #            return false;">Delete this post</a>
  link_to_remote "Delete this post", :update => "posts",
    :url => { :action => "destroy", :id => post.id }

  # Generates: <a href="#" onclick="new Ajax.Updater('emails', '/mail/list_emails', {asynchronous:true, evalScripts:true});
  #            return false;"><img alt="Refresh" src="/images/refresh.png?" /></a>
  link_to_remote(image_tag("refresh"), :update => "emails",
    :url => { :action => "list_emails" })

You can override the generated HTML options by specifying a hash in options[:html].

  link_to_remote "Delete this post", :update => "posts",
    :url  => post_url(@post), :method => :delete,
    :html => { :class  => "destructive" }

You can also specify a hash for options[:update] to allow for easy redirection of output to an other DOM element if a server-side error occurs:

Example:

  # Generates: <a href="#" onclick="new Ajax.Updater({success:'posts',failure:'error'}, '/blog/destroy/5',
  #            {asynchronous:true, evalScripts:true}); return false;">Delete this post</a>
  link_to_remote "Delete this post",
    :url => { :action => "destroy", :id => post.id },
    :update => { :success => "posts", :failure => "error" }

Optionally, you can use the options[:position] parameter to influence how the target DOM element is updated. It must be one of :before, :top, :bottom, or :after.

The method used is by default POST. You can also specify GET or you can simulate PUT or DELETE over POST. All specified with options[:method]

Example:

  # Generates: <a href="#" onclick="new Ajax.Request('/person/4', {asynchronous:true, evalScripts:true, method:'delete'});
  #            return false;">Destroy</a>
  link_to_remote "Destroy", :url => person_url(:id => person), :method => :delete

By default, these remote requests are processed asynchronous during which various JavaScript callbacks can be triggered (for progress indicators and the likes). All callbacks get access to the request object, which holds the underlying XMLHttpRequest.

To access the server response, use request.responseText, to find out the HTTP status, use request.status.

Example:

  # Generates: <a href="#" onclick="new Ajax.Request('/words/undo?n=33', {asynchronous:true, evalScripts:true,
  #            onComplete:function(request){undoRequestCompleted(request)}}); return false;">hello</a>
  word = 'hello'
  link_to_remote word,
    :url => { :action => "undo", :n => word_counter },
    :complete => "undoRequestCompleted(request)"

The callbacks that may be specified are (in order):

You can further refine :success and :failure by adding additional callbacks for specific status codes.

Example:

  # Generates: <a href="#" onclick="new Ajax.Request('/testing/action', {asynchronous:true, evalScripts:true,
  #            on404:function(request){alert('Not found...? Wrong URL...?')},
  #            onFailure:function(request){alert('HTTP Error ' + request.status + '!')}}); return false;">hello</a>
  link_to_remote word,
    :url => { :action => "action" },
    404 => "alert('Not found...? Wrong URL...?')",
    :failure => "alert('HTTP Error ' + request.status + '!')"

A status code callback overrides the success/failure handlers if present.

If you for some reason or another need synchronous processing (that‘ll block the browser while the request is happening), you can specify options[:type] = :synchronous.

You can customize further browser side call logic by passing in JavaScript code snippets via some optional parameters. In their order of use these are:

  :with => "'name=' + $('name').value"

You can generate a link that uses AJAX in the general case, while degrading gracefully to plain link behavior in the absence of JavaScript by setting html_options[:href] to an alternate URL. Note the extra curly braces around the options hash separate it as the second parameter from html_options, the third.

Example:

  link_to_remote "Delete this post",
    { :update => "posts", :url => { :action => "destroy", :id => post.id } },
    :href => url_for(:action => "destroy", :id => post.id)

Observes the field with the DOM ID specified by field_id and calls a callback when its contents have changed. The default callback is an Ajax call. By default the value of the observed field is sent as a parameter with the Ajax call.

Example:

 # Generates: new Form.Element.Observer('suggest', 0.25, function(element, value) {new Ajax.Updater('suggest',
 #         '/testing/find_suggestion', {asynchronous:true, evalScripts:true, parameters:'q=' + value})})
 <%= observe_field :suggest, :url => { :action => :find_suggestion },
      :frequency => 0.25,
      :update => :suggest,
      :with => 'q'
      %>

Required options are either of:

  observe_field("glass", :frequency => 1, :function => "alert('Element changed')")

  new Form.Element.Observer('glass', 1, function(element, value) {alert('Element changed')})

Additional options are:

  :with => "'my_custom_key=' + value"
  :with => "'person[name]=' + prompt('New name')"
  :with => "Form.Element.serialize('other-field')"

  :with => 'name'

  :with => "'name=' + value"

Additionally, you may specify any of the options documented in the Common options section at the top of this document.

Example:

  # Sends params: {:title => 'Title of the book'} when the book_title input
  # field is changed.
  observe_field 'book_title',
    :url => 'http://example.com/books/edit/1',
    :with => 'title'

Observes the form with the DOM ID specified by form_id and calls a callback when its contents have changed. The default callback is an Ajax call. By default all fields of the observed field are sent as parameters with the Ajax call.

The options for observe_form are the same as the options for observe_field. The JavaScript variable value available to the :with option is set to the serialized form by default.

Periodically calls the specified url (options[:url]) every options[:frequency] seconds (default is 10). Usually used to update a specified div (options[:update]) with the results of the remote call. The options for specifying the target with :url and defining callbacks is the same as link_to_remote. Examples:

 # Call get_averages and put its results in 'avg' every 10 seconds
 # Generates:
 #      new PeriodicalExecuter(function() {new Ajax.Updater('avg', '/grades/get_averages',
 #      {asynchronous:true, evalScripts:true})}, 10)
 periodically_call_remote(:url => { :action => 'get_averages' }, :update => 'avg')

 # Call invoice every 10 seconds with the id of the customer
 # If it succeeds, update the invoice DIV; if it fails, update the error DIV
 # Generates:
 #      new PeriodicalExecuter(function() {new Ajax.Updater({success:'invoice',failure:'error'},
 #      '/testing/invoice/16', {asynchronous:true, evalScripts:true})}, 10)
 periodically_call_remote(:url => { :action => 'invoice', :id => customer.id },
    :update => { :success => "invoice", :failure => "error" }

 # Call update every 20 seconds and update the new_block DIV
 # Generates:
 # new PeriodicalExecuter(function() {new Ajax.Updater('news_block', 'update', {asynchronous:true, evalScripts:true})}, 20)
 periodically_call_remote(:url => 'update', :frequency => '20', :update => 'news_block')

Creates a form that will submit using XMLHttpRequest in the background instead of the regular reloading POST arrangement and a scope around a specific resource that is used as a base for questioning about values for the fields.

Resource

Example:

  <% remote_form_for(@post) do |f| %>
    ...
  <% end %>

This will expand to be the same as:

  <% remote_form_for :post, @post, :url => post_path(@post), :html => { :method => :put, :class => "edit_post", :id => "edit_post_45" } do |f| %>
    ...
  <% end %>

Nested Resource

Example:

  <% remote_form_for([@post, @comment]) do |f| %>
    ...
  <% end %>

This will expand to be the same as:

  <% remote_form_for :comment, @comment, :url => post_comment_path(@post, @comment), :html => { :method => :put, :class => "edit_comment", :id => "edit_comment_45" } do |f| %>
    ...
  <% end %>

If you don‘t need to attach a form to a resource, then check out form_remote_tag.

See FormHelper#form_for for additional semantics.

Returns the JavaScript needed for a remote function. Takes the same arguments as link_to_remote.

Example:

  # Generates: <select id="options" onchange="new Ajax.Updater('options',
  # '/testing/update_options', {asynchronous:true, evalScripts:true})">
  <select id="options" onchange="<%= remote_function(:update => "options",
      :url => { :action => :update_options }) %>">
    <option value="0">Hello</option>
    <option value="1">World</option>
  </select>

Returns a button input tag with the element name of name and a value (i.e., display text) of value that will submit form using XMLHttpRequest in the background instead of a regular POST request that reloads the page.

 # Create a button that submits to the create action
 #
 # Generates: <input name="create_btn" onclick="new Ajax.Request('/testing/create',
 #     {asynchronous:true, evalScripts:true, parameters:Form.serialize(this.form)});
 #     return false;" type="button" value="Create" />
 <%= submit_to_remote 'create_btn', 'Create', :url => { :action => 'create' } %>

 # Submit to the remote action update and update the DIV succeed or fail based
 # on the success or failure of the request
 #
 # Generates: <input name="update_btn" onclick="new Ajax.Updater({success:'succeed',failure:'fail'},
 #      '/testing/update', {asynchronous:true, evalScripts:true, parameters:Form.serialize(this.form)});
 #      return false;" type="button" value="Update" />
 <%= submit_to_remote 'update_btn', 'Update', :url => { :action => 'update' },
    :update => { :success => "succeed", :failure => "fail" }

options argument is the same as in form_remote_tag.

Yields a JavaScriptGenerator and returns the generated JavaScript code. Use this to update multiple elements on a page in an Ajax response. See JavaScriptGenerator for more information.

Example:

  update_page do |page|
    page.hide 'spinner'
  end

Works like update_page but wraps the generated JavaScript in a <script> tag. Use this to include generated JavaScript in an ERb template. See JavaScriptGenerator for more information.

html_options may be a hash of <script> attributes to be passed to ActionView::Helpers::JavaScriptHelper#javascript_tag.