Module: ActionView::Helpers::JavaScriptHelper

Includes:
PrototypeHelper
Included in:
UrlHelper
Defined in:
lib/action_view/helpers/javascript_helper.rb

Overview

Provides functionality for working with JavaScript in your views.

Ajax, controls and visual effects

  • For information on using Ajax, see ActionView::Helpers::PrototypeHelper.

  • For information on using controls and visual effects, see ActionView::Helpers::ScriptaculousHelper.

Including the JavaScript libraries into your pages

Rails includes the Prototype JavaScript framework and the Scriptaculous JavaScript controls and visual effects library. If you wish to use these libraries and their helpers (ActionView::Helpers::PrototypeHelper and ActionView::Helpers::ScriptaculousHelper), you must do one of the following:

  • Use <%= javascript_include_tag :defaults %> in the HEAD section of your page (recommended): This function will return references to the JavaScript files created by the rails command in your public/javascripts directory. Using it is recommended as the browser can then cache the libraries instead of fetching all the functions anew on every request.

  • Use <%= javascript_include_tag 'prototype' %>: As above, but will only include the Prototype core library, which means you are able to use all basic AJAX functionality. For the Scriptaculous-based JavaScript helpers, like visual effects, autocompletion, drag and drop and so on, you should use the method described above.

  • Use <%= define_javascript_functions %>: this will copy all the JavaScript support functions within a single script block. Not recommended.

For documentation on javascript_include_tag see ActionView::Helpers::AssetTagHelper.

Constant Summary collapse

JAVASCRIPT_PATH = 
File.join(File.dirname(__FILE__), 'javascripts')

Constants included from PrototypeHelper

PrototypeHelper::AJAX_OPTIONS, PrototypeHelper::CALLBACKS

Instance Method Summary collapse

Methods included from PrototypeHelper

#evaluate_remote_response, #form_remote_tag, #link_to_remote, #observe_field, #observe_form, #periodically_call_remote, #remote_form_for, #remote_function, #submit_to_remote, #update_page, #update_page_tag

Instance Method Details

#button_to_function(name, *args, &block) ⇒ Object

Returns a button that’ll trigger a JavaScript function using the onclick handler.

The function argument can be omitted in favor of an update_page block, which evaluates to a string when the template is rendered (instead of making an Ajax request first).

Examples:

button_to_function "Greeting", "alert('Hello world!')"
button_to_function "Delete", "if (confirm('Really?')) do_delete()"
button_to_function "Details" do |page|
  page[:details].visual_effect :toggle_slide
end
button_to_function "Details", :class => "details_button" do |page|
  page[:details].visual_effect :toggle_slide
end



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# File 'lib/action_view/helpers/javascript_helper.rb', line 113

def button_to_function(name, *args, &block)
  html_options = args.extract_options!
  function = args[0] || ''

  html_options.symbolize_keys!
  function = update_page(&block) if block_given?
  tag(:input, html_options.merge({ 
    :type => "button", :value => name, 
    :onclick => (html_options[:onclick] ? "#{html_options[:onclick]}; " : "") + "#{function};" 
  }))
end

#define_javascript_functions ⇒ Object

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 undefined 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.



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# File 'lib/action_view/helpers/javascript_helper.rb', line 134

def define_javascript_functions
  javascript = "<script type=\"#{Mime::JS}\">"
  
  # load prototype.js and its extensions first 
  prototype_libs = Dir.glob(File.join(JAVASCRIPT_PATH, 'prototype*')).sort.reverse
  prototype_libs.each do |filename| 
    javascript << "\n" << IO.read(filename)
  end
  
  # load other libraries
  (Dir.glob(File.join(JAVASCRIPT_PATH, '*')) - prototype_libs).each do |filename| 
    javascript << "\n" << IO.read(filename)
  end
  javascript << '</script>'
end

#escape_javascript(javascript) ⇒ Object

Escape carrier returns and single and double quotes for JavaScript segments.



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# File 'lib/action_view/helpers/javascript_helper.rb', line 151

def escape_javascript(javascript)
  (javascript || '').gsub('\\','\0\0').gsub('</','<\/').gsub(/\r\n|\n|\r/, "\\n").gsub(/["']/) { |m| "\\#{m}" }
end

#javascript_cdata_section(content) ⇒ Object

:nodoc:



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# File 'lib/action_view/helpers/javascript_helper.rb', line 191

def javascript_cdata_section(content) #:nodoc:
  "\n//#{cdata_section("\n#{content}\n//")}\n"
end

#javascript_tag(content_or_options_with_block = nil, html_options = {}, &block) ⇒ Object

Returns a JavaScript tag with the content inside. Example:

javascript_tag "alert('All is good')"

Returns:

<script type="text/javascript">
//<![CDATA[
alert('All is good')
//]]>
</script>

html_options may be a hash of attributes for the <script> tag. Example:

javascript_tag "alert('All is good')", :defer => 'defer' 
# => <script defer="defer" type="text/javascript">alert('All is good')</script>

Instead of passing the content as an argument, you can also use a block in which case, you pass your html_options as the first parameter.

<% javascript_tag :defer => 'defer' do -%>
  alert('All is good')
<% end -%>



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# File 'lib/action_view/helpers/javascript_helper.rb', line 174

def javascript_tag(content_or_options_with_block = nil, html_options = {}, &block)
  if block_given?
    html_options = content_or_options_with_block if content_or_options_with_block.is_a?(Hash)
    content = capture(&block)
  else
    content = content_or_options_with_block
  end

  javascript_tag = content_tag("script", javascript_cdata_section(content), html_options.merge(:type => Mime::JS))
  
  if block_given? && block_is_within_action_view?(block)
    concat(javascript_tag, block.binding)
  else
    javascript_tag
  end
end

#link_to_function(name, *args, &block) ⇒ Object

Returns a link that will trigger a JavaScript function using the onclick handler and return false after the fact.

The function argument can be omitted in favor of an update_page block, which evaluates to a string when the template is rendered (instead of making an Ajax request first).

Examples:

link_to_function "Greeting", "alert('Hello world!')"
  Produces:
    <a onclick="alert('Hello world!'); return false;" href="#">Greeting</a>

link_to_function(image_tag("delete"), "if (confirm('Really?')) do_delete()")
  Produces:
    <a onclick="if (confirm('Really?')) do_delete(); return false;" href="#">
      <img src="/images/delete.png?" alt="Delete"/>
    </a>

link_to_function("Show me more", nil, :id => "more_link") do |page|
  page[:details].visual_effect  :toggle_blind
  page[:more_link].replace_html "Show me less"
end
  Produces:
    <a href="#" id="more_link" onclick="try {
      $(&quot;details&quot;).visualEffect(&quot;toggle_blind&quot;);
      $(&quot;more_link&quot;).update(&quot;Show me less&quot;);
    } 
    catch (e) { 
      alert('RJS error:\n\n' + e.toString()); 
      alert('$(\&quot;details\&quot;).visualEffect(\&quot;toggle_blind\&quot;);
      \n$(\&quot;more_link\&quot;).update(\&quot;Show me less\&quot;);');
      throw e 
    };
    return false;">Show me more</a>



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# File 'lib/action_view/helpers/javascript_helper.rb', line 82

def link_to_function(name, *args, &block)
  html_options = args.extract_options!
  function = args[0] || ''

  html_options.symbolize_keys!
  function = update_page(&block) if block_given?
  content_tag(
    "a", name, 
    html_options.merge({ 
      :href => html_options[:href] || "#", 
      :onclick => (html_options[:onclick] ? "#{html_options[:onclick]}; " : "") + "#{function}; return false;" 
    })
  )
end