Module: ActionView::Helpers::JavaScriptHelper

Includes:
PrototypeHelper
Included in:
ActionView::Helpers
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.

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

Constant Summary collapse

JS_ESCAPE_MAP =
{
'\\'    => '\\\\',
'</'    => '<\/',
"\r\n"  => '\n',
"\n"    => '\n',
"\r"    => '\n',
'"'     => '\\"',
"'"     => "\\'" }

Constants included from PrototypeHelper

PrototypeHelper::AJAX_OPTIONS, PrototypeHelper::CALLBACKS

Instance Method Summary collapse

Methods included from PrototypeHelper

#remote_function, #update_page, #update_page_tag

Instance Method Details

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

Returns a button with the given name text that'll trigger a JavaScript function using the onclick handler.

The first argument name is used as the button's value or display text.

The next arguments are optional and may include the javascript function definition and a hash of html_options.

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).

The html_options will accept a hash of html attributes for the link tag. Some examples are :class => “nav_button”, :id => “articles_nav_button”

Note: if you choose to specify the javascript function in a block, but would like to pass html_options, set the function parameter to nil

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 118

def button_to_function(name, *args, &block)
  html_options = args.extract_options!.symbolize_keys

  function = block_given? ? update_page(&block) : args[0] || ''
  onclick = "#{"#{html_options[:onclick]}; " if html_options[:onclick]}#{function};"

  tag(:input, html_options.merge(:type => 'button', :value => name, :onclick => onclick))
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 50

def escape_javascript(javascript)
  if javascript
    javascript.gsub(/(\\|<\/|\r\n|[\n\r"'])/) { JS_ESCAPE_MAP[$1] }
  else
    ''
  end
end

#javascript_cdata_section(content) ⇒ Object

:nodoc:


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# File 'lib/action_view/helpers/javascript_helper.rb', line 90

def javascript_cdata_section(content) #:nodoc:
  "\n//#{cdata_section("\n#{content}\n//")}\n".html_safe
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 78

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

  (:script, javascript_cdata_section(content), html_options.merge(:type => Mime::JS))
end

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

The first argument name is used as the link text.

The next arguments are optional and may include the javascript function definition and a hash of html_options.

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).

The html_options will accept a hash of html attributes for the link tag. Some examples are :class => “nav_button”, :id => “articles_nav_button”

Note: if you choose to specify the javascript function in a block, but would like to pass html_options, set the function parameter to nil

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 171

def link_to_function(name, *args, &block)
  html_options = args.extract_options!.symbolize_keys

  function = block_given? ? update_page(&block) : args[0] || ''
  onclick = "#{"#{html_options[:onclick]}; " if html_options[:onclick]}#{function}; return false;"
  href = html_options[:href] || '#'

  (:a, name, html_options.merge(:href => href, :onclick => onclick))
end