Module | ActionView::Helpers::JavaScriptHelper |
In: |
vendor/rails/actionpack/lib/action_view/helpers/javascript_helper.rb
|
Provides a set of helpers for calling JavaScript functions and, most importantly, to call remote methods using what has been labelled AJAX. This means that you can call actions in your controllers without reloading the page, but still update certain parts of it using injections into the DOM. The common use case is having a form that adds a new element to a list without reloading the page.
To be able to use the JavaScript helpers, you must either call <%= define_javascript_functions %> (which returns all the JavaScript support functions in a <script> block) or reference the JavaScript library using <%= javascript_include_tag "prototype" %> (which looks for the library in /javascripts/prototype.js). The latter is recommended as the browser can then cache the library instead of fetching all the functions anew on every request.
If you’re the visual type, there’s an AJAX movie demonstrating the use of form_remote_tag.
CALLBACKS | = | [:uninitialized, :loading, :loaded, :interactive, :complete, :failure].push((100..599).to_a).flatten |
AJAX_OPTIONS | = | [ :before, :after, :condition, :url, :asynchronous, :method, :insertion, :position, :form, :with, :update, :script ].concat(CALLBACKS) |
JAVASCRIPT_PATH | = | File.join(File.dirname(__FILE__), 'javascripts') |
Adds AJAX autocomplete functionality to the text input field with the DOM ID specified by field_id.
This function expects that the called action returns a HTML <ul> list, or nothing if no entries should be displayed for autocompletion.
You‘ll probably want to turn the browser’s built-in autocompletion off, su be sure to include a autocomplete="off" attribute with your text input field.
Required options are:
:url: | Specifies the DOM ID of the element whose innerHTML should be updated with the autocomplete entries returned by XMLHttpRequest. |
Addtional options are:
:update: | Specifies the DOM ID of the element whose innerHTML should be updated with the autocomplete entries returned by the AJAX request. Defaults to field_id + ‘_auto_complete‘ |
:with: | A JavaScript expression specifying the parameters for the XMLHttpRequest. This defaults to ‘fieldname=value’. |
:indicator: | Specifies the DOM ID of an elment which will be displayed while autocomplete is running. |
# File vendor/rails/actionpack/lib/action_view/helpers/javascript_helper.rb, line 359 359: def auto_complete_field(field_id, options = {}) 360: function = "new Ajax.Autocompleter(" 361: function << "'#{field_id}', " 362: function << "'" + (options[:update] || "#{field_id}_auto_complete") + "', " 363: function << "'#{url_for(options[:url])}'" 364: 365: js_options = {} 366: if options[:tokens] and options[:tokens].kind_of?(Array) 367: js_options[:tokens] = "['#{options[:tokens].join('\',\'')}']" 368: elsif options[:tokens] 369: js_options[:tokens] = "'#{options[:tokens]}'" if options[:tokens] 370: end 371: js_options[:callback] = "function(element, value) { return #{options[:with]} }" if options[:with] 372: js_options[:indicator] = "'#{options[:indicator]}'" if options[:indicator] 373: function << (', ' + options_for_javascript(js_options) + ')') 374: 375: javascript_tag(function) 376: end
Use this method in your view to generate a return for the AJAX automplete requests.
Example action:
def auto_complete_for_item_title @items = Item.find(:all, :conditions => [ 'LOWER(description) LIKE ?', '%' + request.raw_post.downcase + '%' ]) render :inline => '<%= auto_complete_result(@items, 'description') %>' end
The auto_complete_result can of course also be called from a view belonging to the auto_complete action if you need to decorate it further.
# File vendor/rails/actionpack/lib/action_view/helpers/javascript_helper.rb, line 391 391: def auto_complete_result(entries, field, phrase = nil) 392: return unless entries 393: items = entries.map { |entry| content_tag("li", phrase ? highlight(entry[field], phrase) : h(entry[field])) } 394: content_tag("ul", items) 395: end
Includes the Action Pack JavaScript libraries inside a single <script> tag. The function first includes prototype.js and then its core extensions, (determined by filenames starting with "prototype"). Afterwards, any additional scripts will be included in random order.
Note: The recommended approach is to copy the contents of lib/action_view/helpers/javascripts/ into your application’s public/javascripts/ directory, and use javascript_include_tag to create remote <script> links.
# File vendor/rails/actionpack/lib/action_view/helpers/javascript_helper.rb, line 275 275: def define_javascript_functions 276: javascript = '<script type="text/javascript">' 277: 278: # load prototype.js and its extensions first 279: prototype_libs = Dir.glob(File.join(JAVASCRIPT_PATH, 'prototype*')).sort.reverse 280: prototype_libs.each do |filename| 281: javascript << "\n" << IO.read(filename) 282: end 283: 284: # load other librairies 285: (Dir.glob(File.join(JAVASCRIPT_PATH, '*')) - prototype_libs).each do |filename| 286: javascript << "\n" << IO.read(filename) 287: end 288: javascript << '</script>' 289: end
Makes the element with the DOM ID specified by element_id draggable.
Example:
<%= draggable_element("my_image", :revert => true)
You can change the behaviour with various options, see script.aculo.us for more documentation.
# File vendor/rails/actionpack/lib/action_view/helpers/javascript_helper.rb, line 472 472: def draggable_element(element_id, options = {}) 473: javascript_tag("new Draggable('#{element_id}', #{options_for_javascript(options)})") 474: end
Makes the element with the DOM ID specified by element_id receive dropped draggable elements (created by draggable_element). and make an AJAX call By default, the action called gets the DOM ID of the element as parameter.
Example:
<%= drop_receiving_element("my_cart", :url => { :controller => "cart", :action => "add" }) %>
You can change the behaviour with various options, see script.aculo.us for more documentation.
# File vendor/rails/actionpack/lib/action_view/helpers/javascript_helper.rb, line 486 486: def drop_receiving_element(element_id, options = {}) 487: options[:with] ||= "'id=' + encodeURIComponent(element.id)" 488: options[:onDrop] ||= "function(element){" + remote_function(options) + "}" 489: options.delete_if { |key, value| AJAX_OPTIONS.include?(key) } 490: 491: if options[:accept] and options[:accept].kind_of?(Array) 492: options[:accept] = "['#{options[:accept].join('\',\'')}']" 493: elsif options[:accept] 494: options[:accept] = "'#{options[:accept]}'" if options[:accept] 495: end 496: 497: options[:hoverclass] = "'#{options[:hoverclass]}'" if options[:hoverclass] 498: 499: javascript_tag("Droppables.add('#{element_id}', #{options_for_javascript(options)})") 500: end
Escape carrier returns and single and double quotes for JavaScript segments.
# File vendor/rails/actionpack/lib/action_view/helpers/javascript_helper.rb, line 503 503: def escape_javascript(javascript) 504: (javascript || '').gsub(/\r\n|\n|\r/, "\\n").gsub(/["']/) { |m| "\\#{m}" } 505: end
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.
# File vendor/rails/actionpack/lib/action_view/helpers/javascript_helper.rb, line 234 234: def evaluate_remote_response 235: "eval(request.responseText)" 236: end
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
form_remote_tag :html => { :action => url_for(:controller => "some", :action => "place") }
By default the fall-through action is the same as the one specified in the :url (and the default method is :post).
# File vendor/rails/actionpack/lib/action_view/helpers/javascript_helper.rb, line 142 142: def form_remote_tag(options = {}) 143: options[:form] = true 144: 145: options[:html] ||= {} 146: options[:html][:onsubmit] = "#{remote_function(options)}; return false;" 147: options[:html][:action] = options[:html][:action] || url_for(options[:url]) 148: options[:html][:method] = options[:html][:method] || "post" 149: 150: tag("form", options[:html], true) 151: end
Returns a JavaScript tag with the content inside. Example:
javascript_tag "alert('All is good')" # => <script type="text/javascript">alert('All is good')</script>
# File vendor/rails/actionpack/lib/action_view/helpers/javascript_helper.rb, line 509 509: def javascript_tag(content) 510: content_tag("script", content, :type => "text/javascript") 511: end
Returns a link that’ll trigger a javascript function using the onclick handler and return false after the fact.
Examples:
link_to_function "Greeting", "alert('Hello world!')" link_to_function(image_tag("delete"), "if confirm('Really?'){ do_delete(); }")
# File vendor/rails/actionpack/lib/action_view/helpers/javascript_helper.rb, line 32 32: def link_to_function(name, function, html_options = {}) 33: content_tag( 34: "a", name, 35: {:href => "#", :onclick => "#{function}; return false;"}.merge(html_options.symbolize_keys) 36: ) 37: 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 either render_partial or render_partial_collection.
Examples:
link_to_remote "Delete this post", :update => "posts", :url => { :action => "destroy", :id => post.id } link_to_remote(image_tag("refresh"), :update => "emails", :url => { :action => "list_emails" })
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:
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.
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:
link_to_remote word, :url => { :action => "undo", :n => word_counter }, :complete => "undoRequestCompleted(request)"
The callbacks that may be specified are (in order):
: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 further refine :success and :failure by adding additional callbacks for specific status codes:
Example:
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:
:confirm: | Adds confirmation dialog. |
:condition: | Perform remote request conditionally by this expression. Use this to describe browser-side conditions when request should not be initiated. |
:before: | Called before request is initiated. |
:after: | Called immediately after request was initiated and before :loading. |
# File vendor/rails/actionpack/lib/action_view/helpers/javascript_helper.rb, line 119 119: def link_to_remote(name, options = {}, html_options = {}) 120: link_to_function(name, remote_function(options), html_options) 121: end
Observes the field with the DOM ID specified by field_id and makes an AJAX call when its contents have changed.
Required options are:
:url: | url_for-style options for the action to call when the field has changed. |
Additional options are:
:frequency: | The frequency (in seconds) at which changes to this field will be detected. Set this to a value greater than zero to use time based observation instead of event based observation. |
:update: | Specifies the DOM ID of the element whose innerHTML should be updated with the XMLHttpRequest response text. |
:with: | A JavaScript expression specifying the parameters for the XMLHttpRequest. This defaults to ‘value’, which in the evaluated context refers to the new field value. |
Additionally, you may specify any of the options documented in +link_to_remote.
# File vendor/rails/actionpack/lib/action_view/helpers/javascript_helper.rb, line 313 313: def observe_field(field_id, options = {}) 314: if options[:frequency] 315: build_observer('Form.Element.Observer', field_id, options) 316: else 317: build_observer('Form.Element.EventObserver', field_id, options) 318: end 319: end
Like observe_field, but operates on an entire form identified by the DOM ID form_id. options are the same as observe_field, except the default value of the :with option evaluates to the serialized (request string) value of the form.
# File vendor/rails/actionpack/lib/action_view/helpers/javascript_helper.rb, line 325 325: def observe_form(form_id, options = {}) 326: if options[:frequency] 327: build_observer('Form.Observer', form_id, options) 328: else 329: build_observer('Form.EventObserver', form_id, options) 330: end 331: end
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.
# File vendor/rails/actionpack/lib/action_view/helpers/javascript_helper.rb, line 126 126: def periodically_call_remote(options = {}) 127: frequency = options[:frequency] || 10 # every ten seconds by default 128: code = "new PeriodicalExecuter(function() {#{remote_function(options)}}, #{frequency})" 129: content_tag("script", code, options[:html_options] || {}) 130: end
Makes the element with the DOM ID specified by element_id sortable by drag-and-drop and make an AJAX call whenever the sort order has changed. By default, the action called gets the serialized sortable element as parameters.
Example:
<%= sortable_element("my_list", :url => { :action => "order" }) %>
In the example, the action gets a "my_list" array parameter containing the values of the ids of elements the sortable consists of, in the current order.
You can change the behaviour with various options, see script.aculo.us for more documentation.
# File vendor/rails/actionpack/lib/action_view/helpers/javascript_helper.rb, line 447 447: def sortable_element(element_id, options = {}) 448: options[:with] ||= "Sortable.serialize('#{element_id}')" 449: options[:onUpdate] ||= "function(){" + remote_function(options) + "}" 450: options.delete_if { |key, value| AJAX_OPTIONS.include?(key) } 451: 452: [:tag, :overlap, :constraint, :handle].each do |option| 453: options[option] = "'#{options[option]}'" if options[option] 454: end 455: 456: if options[:containment] and options[:containment].kind_of?(Array) 457: options[:containment] = "['#{options[:containment].join('\',\'')}']" 458: elsif options[:containment] 459: options[:containment] = "'#{options[:containment]}'" if options[:containment] 460: end 461: 462: javascript_tag("Sortable.create('#{element_id}', #{options_for_javascript(options)})") 463: end
Returns a button input tag that will submit form using XMLHttpRequest in the background instead of regular reloading POST arrangement. options argument is the same as in form_remote_tag
# File vendor/rails/actionpack/lib/action_view/helpers/javascript_helper.rb, line 155 155: def submit_to_remote(name, value, options = {}) 156: options[:with] = 'Form.serialize(this.form)' 157: 158: options[:html] ||= {} 159: options[:html][:type] = 'button' 160: options[:html][:onclick] = "#{remote_function(options)}; return false;" 161: options[:html][:name] = name 162: options[:html][:value] = value 163: 164: tag("input", options[:html], false) 165: end
Wrapper for text_field with added AJAX autocompletion functionality.
In your controller, you’ll need to define an action called auto_complete_for_object_method to respond the AJAX calls,
See the RDoc on ActionController::AutoComplete to learn more about this.
# File vendor/rails/actionpack/lib/action_view/helpers/javascript_helper.rb, line 403 403: def text_field_with_auto_complete(object, method, tag_options = {}, completion_options = {}) 404: (completion_options[:skip_style] ? "" : auto_complete_stylesheet) + 405: text_field(object, method, { :autocomplete => "off" }.merge!(tag_options)) + 406: content_tag("div", "", :id => "#{object}_#{method}_auto_complete", :class => "auto_complete") + 407: auto_complete_field("#{object}_#{method}", { :url => { :action => "auto_complete_for_#{object}_#{method}" } }.update(completion_options)) 408: end
Returns a Javascript function (or expression) that’ll update a DOM element according to the options passed.
Examples:
<%= javascript_tag(update_element_function( "products", :position => :bottom, :content => "<p>New product!</p>")) %> <% replacement_function = update_element_function("products") do %> <p>Product 1</p> <p>Product 2</p> <% end %> <%= javascript_tag(replacement_function) %>
This method can also be used in combination with remote method call where the result is evaluated afterwards to cause multiple updates on a page. Example:
# Calling view <%= form_remote_tag :url => { :action => "buy" }, :complete => evaluate_remote_response %> all the inputs here... # Controller action def buy @product = Product.find(1) end # Returning view <%= update_element_function( "cart", :action => :update, :position => :bottom, :content => "<p>New Product: #{@product.name}</p>")) %> <% update_element_function("status", :binding => binding) do %> You've bought a new product! <% end %>
Notice how the second call doesn’t need to be in an ERb output block since it uses a block and passes in the binding to render directly. This trick will however only work in ERb (not Builder or other template forms).
# File vendor/rails/actionpack/lib/action_view/helpers/javascript_helper.rb, line 205 205: def update_element_function(element_id, options = {}, &block) 206: 207: content = escape_javascript(options[:content] || '') 208: content = escape_javascript(capture(&block)) if block 209: 210: javascript_function = case (options[:action] || :update) 211: when :update 212: if options[:position] 213: "new Insertion.#{options[:position].to_s.camelize}('#{element_id}','#{content}')" 214: else 215: "$('#{element_id}').innerHTML = '#{content}'" 216: end 217: 218: when :empty 219: "$('#{element_id}').innerHTML = ''" 220: 221: when :remove 222: "Element.remove('#{element_id}')" 223: 224: else 225: raise ArgumentError, "Invalid action, choose one of :update, :remove, :empty" 226: end 227: 228: javascript_function << ";\n" 229: options[:binding] ? concat(javascript_function, options[:binding]) : javascript_function 230: end
Returns a JavaScript snippet to be used on the AJAX callbacks for starting visual effects.
Example:
<%= link_to_remote "Reload", :update => "posts", :url => { :action => "reload" }, :complete => visual_effect(:highlight, "posts", :duration => 0.5 )
If no element_id is given, it assumes "element" which should be a local variable in the generated JavaScript execution context. This can be used for example with drop_receiving_element:
<%= drop_receving_element (...), :loading => visual_effect(:fade) %>
This would fade the element that was dropped on the drop receiving element.
You can change the behaviour with various options, see script.aculo.us for more documentation.
# File vendor/rails/actionpack/lib/action_view/helpers/javascript_helper.rb, line 428 428: def visual_effect(name, element_id = false, js_options = {}) 429: element = element_id ? "'#{element_id}'" : "element" 430: "new Effect.#{name.to_s.camelize}(#{element},#{options_for_javascript(js_options)});" 431: end