Module ActionView::Helpers::JavaScriptHelper
In: vendor/rails/actionpack/lib/action_view/helpers/javascript_helper.rb

Provides functionality for working with JavaScript in your views.

Ajax, controls and visual effects

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.

Methods

array_or_string_for_javascript   button_to_function   define_javascript_functions   escape_javascript   javascript_tag   link_to_function   options_for_javascript  

Constants

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

Public Instance methods

button_to_function(name, function, html_options = {})

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(); }")

[Source]

    # File vendor/rails/actionpack/lib/action_view/helpers/javascript_helper.rb, line 67
67:       def button_to_function(name, function, html_options = {})
68:         html_options.symbolize_keys!
69:         tag(:input, html_options.merge({ 
70:           :type => "button", :value => name, 
71:           :onclick => (html_options[:onclick] ? "#{html_options[:onclick]}; " : "") + "#{function};" 
72:         }))
73:       end
define_javascript_functions()

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.

[Source]

    # File vendor/rails/actionpack/lib/action_view/helpers/javascript_helper.rb, line 84
84:       def define_javascript_functions
85:         javascript = '<script type="text/javascript">'
86:         
87:         # load prototype.js and its extensions first 
88:         prototype_libs = Dir.glob(File.join(JAVASCRIPT_PATH, 'prototype*')).sort.reverse
89:         prototype_libs.each do |filename| 
90:           javascript << "\n" << IO.read(filename)
91:         end
92:         
93:         # load other librairies
94:         (Dir.glob(File.join(JAVASCRIPT_PATH, '*')) - prototype_libs).each do |filename| 
95:           javascript << "\n" << IO.read(filename)
96:         end
97:         javascript << '</script>'
98:       end
escape_javascript(javascript)

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

[Source]

     # File vendor/rails/actionpack/lib/action_view/helpers/javascript_helper.rb, line 101
101:       def escape_javascript(javascript)
102:         (javascript || '').gsub(/\r\n|\n|\r/, "\\n").gsub(/["']/) { |m| "\\#{m}" }
103:       end
javascript_tag(content)

Returns a JavaScript tag with the content inside. Example: 

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

[Source]

     # File vendor/rails/actionpack/lib/action_view/helpers/javascript_helper.rb, line 107
107:       def javascript_tag(content)
108:         content_tag("script", javascript_cdata_section(content), :type => "text/javascript")
109:       end
link_to_function(name, function, html_options = {})

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(); }")

[Source]

    # File vendor/rails/actionpack/lib/action_view/helpers/javascript_helper.rb, line 50
50:       def link_to_function(name, function, html_options = {})
51:         html_options.symbolize_keys!
52:         content_tag(
53:           "a", name, 
54:           html_options.merge({ 
55:             :href => html_options[:href] || "#", 
56:             :onclick => (html_options[:onclick] ? "#{html_options[:onclick]}; " : "") + "#{function}; return false;" 
57:           })
58:         )
59:       end

Protected Instance methods

array_or_string_for_javascript(option)

[Source]

     # File vendor/rails/actionpack/lib/action_view/helpers/javascript_helper.rb, line 120
120:       def array_or_string_for_javascript(option)
121:         js_option = if option.kind_of?(Array)
122:           "['#{option.join('\',\'')}']"
123:         elsif !option.nil?
124:           "'#{option}'"
125:         end
126:         js_option
127:       end
options_for_javascript(options)

[Source]

     # File vendor/rails/actionpack/lib/action_view/helpers/javascript_helper.rb, line 116
116:       def options_for_javascript(options)
117:         '{' + options.map {|k, v| "#{k}:#{v}"}.sort.join(', ') + '}'
118:       end

[Validate]