JavaScriptGenerator generates blocks of JavaScript code that allow you to change the content and presentation of multiple DOM elements. Use this in your Ajax response bodies, either in a <script> tag or as plain JavaScript sent with a Content-type of "text/javascript".

Create new instances with PrototypeHelper#update_page or with ActionController::Base#render, then call insert_html, replace_html, remove, show, hide, visual_effect, or any other of the built-in methods on the yielded generator in any order you like to modify the content and appearance of the current page.

Example:

  # Generates:
  #     new Element.insert("list", { bottom: "<li>Some item</li>" });
  #     new Effect.Highlight("list");
  #     ["status-indicator", "cancel-link"].each(Element.hide);
  update_page do |page|
    page.insert_html :bottom, 'list', "<li>#{@item.name}</li>"
    page.visual_effect :highlight, 'list'
    page.hide 'status-indicator', 'cancel-link'
  end

Helper methods can be used in conjunction with JavaScriptGenerator. When a helper method is called inside an update block on the page object, that method will also have access to a page object.

Example:

  module ApplicationHelper
    def update_time
      page.replace_html 'time', Time.now.to_s(:db)
      page.visual_effect :highlight, 'time'
    end
  end

  # Controller action
  def poll
    render(:update) { |page| page.update_time }
  end

Calls to JavaScriptGenerator not matching a helper method below generate a proxy to the JavaScript Class named by the method called.

Examples:

  # Generates:
  #     Foo.init();
  update_page do |page|
    page.foo.init
  end

  # Generates:
  #     Event.observe('one', 'click', function () {
  #       $('two').show();
  #     });
  update_page do |page|
    page.event.observe('one', 'click') do |p|
     p[:two].show
    end
  end

You can also use PrototypeHelper#update_page_tag instead of PrototypeHelper#update_page to wrap the generated JavaScript in a <script> tag.

Methods
Public Instance methods
<<(javascript)

Writes raw JavaScript to the page.

Example:

 page << "alert('JavaScript with Prototype.');"
     # File actionpack/lib/action_view/helpers/prototype_helper.rb, line 926
926:           def <<(javascript)
927:             @lines << javascript
928:           end
[](id)

Returns a element reference by finding it through id in the DOM. This element can then be used for further method calls. Examples:

  page['blank_slate']                  # => $('blank_slate');
  page['blank_slate'].show             # => $('blank_slate').show();
  page['blank_slate'].show('first').up # => $('blank_slate').show('first').up();

You can also pass in a record, which will use ActionController::RecordIdentifier.dom_id to lookup the correct id:

  page[@post]     # => $('post_45')
  page[Post.new]  # => $('new_post')
     # File actionpack/lib/action_view/helpers/prototype_helper.rb, line 677
677:           def [](id)
678:             case id
679:               when String, Symbol, NilClass
680:                 JavaScriptElementProxy.new(self, id)
681:               else
682:                 JavaScriptElementProxy.new(self, ActionController::RecordIdentifier.dom_id(id))
683:             end
684:           end
alert(message)

Displays an alert dialog with the given message.

Example:

  # Generates: alert('This message is from Rails!')
  page.alert('This message is from Rails!')
     # File actionpack/lib/action_view/helpers/prototype_helper.rb, line 849
849:           def alert(message)
850:             call 'alert', message
851:           end
assign(variable, value)

Assigns the JavaScript variable the given value.

Examples:

 # Generates: my_string = "This is mine!";
 page.assign 'my_string', 'This is mine!'

 # Generates: record_count = 33;
 page.assign 'record_count', 33

 # Generates: tabulated_total = 47
 page.assign 'tabulated_total', @total_from_cart
     # File actionpack/lib/action_view/helpers/prototype_helper.rb, line 917
917:           def assign(variable, value)
918:             record "#{variable} = #{javascript_object_for(value)}"
919:           end
call(function, *arguments, &block)

Calls the JavaScript function, optionally with the given arguments.

If a block is given, the block will be passed to a new JavaScriptGenerator; the resulting JavaScript code will then be wrapped inside function() { … } and passed as the called function‘s final argument.

Examples:

  # Generates: Element.replace(my_element, "My content to replace with.")
  page.call 'Element.replace', 'my_element', "My content to replace with."

  # Generates: alert('My message!')
  page.call 'alert', 'My message!'

  # Generates:
  #     my_method(function() {
  #       $("one").show();
  #       $("two").hide();
  #    });
  page.call(:my_method) do |p|
     p[:one].show
     p[:two].hide
  end
     # File actionpack/lib/action_view/helpers/prototype_helper.rb, line 900
900:           def call(function, *arguments, &block)
901:             record "#{function}(#{arguments_for_call(arguments, block)})"
902:           end
delay(seconds = 1) {|| ...}

Executes the content of the block after a delay of seconds. Example:

  # Generates:
  #     setTimeout(function() {
  #     ;
  #     new Effect.Fade("notice",{});
  #     }, 20000);
  page.delay(20) do
    page.visual_effect :fade, 'notice'
  end
     # File actionpack/lib/action_view/helpers/prototype_helper.rb, line 940
940:           def delay(seconds = 1)
941:             record "setTimeout(function() {\n\n"
942:             yield
943:             record "}, #{(seconds * 1000).to_i})"
944:           end
draggable(id, options = {})

Creates a script.aculo.us draggable element. See ActionView::Helpers::ScriptaculousHelper for more information.

     # File actionpack/lib/action_view/helpers/prototype_helper.rb, line 962
962:           def draggable(id, options = {})
963:             record @context.send(:draggable_element_js, id, options)
964:           end
drop_receiving(id, options = {})

Creates a script.aculo.us drop receiving element. See ActionView::Helpers::ScriptaculousHelper for more information.

     # File actionpack/lib/action_view/helpers/prototype_helper.rb, line 968
968:           def drop_receiving(id, options = {})
969:             record @context.send(:drop_receiving_element_js, id, options)
970:           end
hide(*ids)

Hides the visible DOM elements with the given ids.

Example:

 # Hide a few people
 # Generates: ["person_29", "person_9", "person_0"].each(Element.hide);
 page.hide 'person_29', 'person_9', 'person_0'
     # File actionpack/lib/action_view/helpers/prototype_helper.rb, line 827
827:           def hide(*ids)
828:             loop_on_multiple_args 'Element.hide', ids
829:           end
insert_html(position, id, *options_for_render)

Inserts HTML at the specified position relative to the DOM element identified by the given id.

position may be one of:

:top:HTML is inserted inside the element, before the element‘s existing content.
:bottom:HTML is inserted inside the element, after the element‘s existing content.
:before:HTML is inserted immediately preceding the element.
:after:HTML is inserted immediately following the element.

options_for_render may be either a string of HTML to insert, or a hash of options to be passed to ActionView::Base#render. For example:

  # Insert the rendered 'navigation' partial just before the DOM
  # element with ID 'content'.
  # Generates: Element.insert("content", { before: "-- Contents of 'navigation' partial --" });
  page.insert_html :before, 'content', :partial => 'navigation'

  # Add a list item to the bottom of the <ul> with ID 'list'.
  # Generates: Element.insert("list", { bottom: "<li>Last item</li>" });
  page.insert_html :bottom, 'list', '<li>Last item</li>'
     # File actionpack/lib/action_view/helpers/prototype_helper.rb, line 742
742:           def insert_html(position, id, *options_for_render)
743:             content = javascript_object_for(render(*options_for_render))
744:             record "Element.insert(\"#{id}\", { #{position.to_s.downcase}: #{content} });"
745:           end
literal(code)

Returns an object whose to_json evaluates to code. Use this to pass a literal JavaScript expression as an argument to another JavaScriptGenerator method.

     # File actionpack/lib/action_view/helpers/prototype_helper.rb, line 688
688:           def literal(code)
689:             ::ActiveSupport::JSON::Variable.new(code.to_s)
690:           end
redirect_to(location)

Redirects the browser to the given location using JavaScript, in the same form as url_for.

Examples:

 # Generates: window.location.href = "/mycontroller";
 page.redirect_to(:action => 'index')

 # Generates: window.location.href = "/account/signup";
 page.redirect_to(:controller => 'account', :action => 'signup')
     # File actionpack/lib/action_view/helpers/prototype_helper.rb, line 862
862:           def redirect_to(location)
863:             url = location.is_a?(String) ? location : @context.url_for(location)
864:             record "window.location.href = #{url.inspect}"
865:           end
reload()

Reloads the browser‘s current location using JavaScript

Examples:

 # Generates: window.location.reload();
 page.reload
     # File actionpack/lib/action_view/helpers/prototype_helper.rb, line 873
873:           def reload
874:             record 'window.location.reload()'
875:           end
remove(*ids)

Removes the DOM elements with the given ids from the page.

Example:

 # Remove a few people
 # Generates: ["person_23", "person_9", "person_2"].each(Element.remove);
 page.remove 'person_23', 'person_9', 'person_2'
     # File actionpack/lib/action_view/helpers/prototype_helper.rb, line 803
803:           def remove(*ids)
804:             loop_on_multiple_args 'Element.remove', ids
805:           end
replace(id, *options_for_render)

Replaces the "outer HTML" (i.e., the entire element, not just its contents) of the DOM element with the given id.

options_for_render may be either a string of HTML to insert, or a hash of options to be passed to ActionView::Base#render. For example:

  # Replace the DOM element having ID 'person-45' with the
  # 'person' partial for the appropriate object.
  page.replace 'person-45', :partial => 'person', :object => @person

This allows the same partial that is used for the insert_html to be also used for the input to replace without resorting to the use of wrapper elements.

Examples:

  <div id="people">
    <%= render :partial => 'person', :collection => @people %>
  </div>

  # Insert a new person
  #
  # Generates: new Insertion.Bottom({object: "Matz", partial: "person"}, "");
  page.insert_html :bottom, :partial => 'person', :object => @person

  # Replace an existing person

  # Generates: Element.replace("person_45", "-- Contents of partial --");
  page.replace 'person_45', :partial => 'person', :object => @person
     # File actionpack/lib/action_view/helpers/prototype_helper.rb, line 791
791:           def replace(id, *options_for_render)
792:             call 'Element.replace', id, render(*options_for_render)
793:           end
replace_html(id, *options_for_render)

Replaces the inner HTML of the DOM element with the given id.

options_for_render may be either a string of HTML to insert, or a hash of options to be passed to ActionView::Base#render. For example:

  # Replace the HTML of the DOM element having ID 'person-45' with the
  # 'person' partial for the appropriate object.
  # Generates:  Element.update("person-45", "-- Contents of 'person' partial --");
  page.replace_html 'person-45', :partial => 'person', :object => @person
     # File actionpack/lib/action_view/helpers/prototype_helper.rb, line 757
757:           def replace_html(id, *options_for_render)
758:             call 'Element.update', id, render(*options_for_render)
759:           end
select(pattern)

Returns a collection reference by finding it through a CSS pattern in the DOM. This collection can then be used for further method calls. Examples:

  page.select('p')                      # => $$('p');
  page.select('p.welcome b').first      # => $$('p.welcome b').first();
  page.select('p.welcome b').first.hide # => $$('p.welcome b').first().hide();

You can also use prototype enumerations with the collection. Observe:

  # Generates: $$('#items li').each(function(value) { value.hide(); });
  page.select('#items li').each do |value|
    value.hide
  end

Though you can call the block param anything you want, they are always rendered in the javascript as ‘value, index.’ Other enumerations, like collect() return the last statement:

  # Generates: var hidden = $$('#items li').collect(function(value, index) { return value.hide(); });
  page.select('#items li').collect('hidden') do |item|
    item.hide
  end
     # File actionpack/lib/action_view/helpers/prototype_helper.rb, line 714
714:           def select(pattern)
715:             JavaScriptElementCollectionProxy.new(self, pattern)
716:           end
show(*ids)

Shows hidden DOM elements with the given ids.

Example:

 # Show a few people
 # Generates: ["person_6", "person_13", "person_223"].each(Element.show);
 page.show 'person_6', 'person_13', 'person_223'
     # File actionpack/lib/action_view/helpers/prototype_helper.rb, line 815
815:           def show(*ids)
816:             loop_on_multiple_args 'Element.show', ids
817:           end
sortable(id, options = {})

Creates a script.aculo.us sortable element. Useful to recreate sortable elements after items get added or deleted. See ActionView::Helpers::ScriptaculousHelper for more information.

     # File actionpack/lib/action_view/helpers/prototype_helper.rb, line 956
956:           def sortable(id, options = {})
957:             record @context.send(:sortable_element_js, id, options)
958:           end
toggle(*ids)

Toggles the visibility of the DOM elements with the given ids. Example:

 # Show a few people
 # Generates: ["person_14", "person_12", "person_23"].each(Element.toggle);
 page.toggle 'person_14', 'person_12', 'person_23'      # Hides the elements
 page.toggle 'person_14', 'person_12', 'person_23'      # Shows the previously hidden elements
     # File actionpack/lib/action_view/helpers/prototype_helper.rb, line 839
839:           def toggle(*ids)
840:             loop_on_multiple_args 'Element.toggle', ids
841:           end
visual_effect(name, id = nil, options = {})

Starts a script.aculo.us visual effect. See ActionView::Helpers::ScriptaculousHelper for more information.

     # File actionpack/lib/action_view/helpers/prototype_helper.rb, line 948
948:           def visual_effect(name, id = nil, options = {})
949:             record @context.send(:visual_effect, name, id, options)
950:           end