Module: ActionView::Helpers::JavaScriptHelper

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')

Instance Method Summary collapse

Instance Method Details

#button_to_function(name, function, html_options = {}) ⇒ Object

Returns a link that'll trigger a JavaScript function using the onclick handler.

Examples:

button_to_function "Greeting", "alert('Hello world!')"
button_to_function "Delete", "if confirm('Really?'){ do_delete(); }")

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# File 'lib/action_view/helpers/javascript_helper.rb', line 67

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

#define_javascript_functionsObject

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 84

def define_javascript_functions
  javascript = '<script type="text/javascript">'
  
  # 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 librairies
  (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 101

def escape_javascript(javascript)
  (javascript || '').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 111

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

#javascript_tag(content) ⇒ Object

Returns a JavaScript tag with the content inside. Example:

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

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# File 'lib/action_view/helpers/javascript_helper.rb', line 107

def javascript_tag(content)
  ("script", javascript_cdata_section(content), :type => "text/javascript")
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(); }")

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# File 'lib/action_view/helpers/javascript_helper.rb', line 50

def link_to_function(name, function, html_options = {})
  html_options.symbolize_keys!
  (
    "a", name, 
    html_options.merge({ 
      :href => html_options[:href] || "#", 
      :onclick => (html_options[:onclick] ? "#{html_options[:onclick]}; " : "") + "#{function}; return false;" 
    })
  )
end