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.
- array_or_string_for_javascript
- button_to_function
- define_javascript_functions
- escape_javascript
- javascript_tag
- link_to_function
- options_for_javascript
JAVASCRIPT_PATH | = | File.join(File.dirname(__FILE__), 'javascripts') |
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 vendor/rails/actionpack/lib/action_view/helpers/javascript_helper.rb, line 113 113: def button_to_function(name, *args, &block) 114: html_options = args.last.is_a?(Hash) ? args.pop : {} 115: function = args[0] || '' 116: 117: html_options.symbolize_keys! 118: function = update_page(&block) if block_given? 119: tag(:input, html_options.merge({ 120: :type => "button", :value => name, 121: :onclick => (html_options[:onclick] ? "#{html_options[:onclick]}; " : "") + "#{function};" 122: })) 123: 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 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 vendor/rails/actionpack/lib/action_view/helpers/javascript_helper.rb, line 134 134: def define_javascript_functions 135: javascript = '<script type="text/javascript">' 136: 137: # load prototype.js and its extensions first 138: prototype_libs = Dir.glob(File.join(JAVASCRIPT_PATH, 'prototype*')).sort.reverse 139: prototype_libs.each do |filename| 140: javascript << "\n" << IO.read(filename) 141: end 142: 143: # load other librairies 144: (Dir.glob(File.join(JAVASCRIPT_PATH, '*')) - prototype_libs).each do |filename| 145: javascript << "\n" << IO.read(filename) 146: end 147: javascript << '</script>' 148: end
Escape carrier returns and single and double quotes for JavaScript segments.
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# File vendor/rails/actionpack/lib/action_view/helpers/javascript_helper.rb, line 151 151: def escape_javascript(javascript) 152: (javascript || '').gsub('\\','\0\0').gsub(/\r\n|\n|\r/, "\\n").gsub(/["']/) { |m| "\\#{m}" } 153: end
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 => 'true' # => <script defer="true" type="text/javascript">alert('All is good')</script>
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# File vendor/rails/actionpack/lib/action_view/helpers/javascript_helper.rb, line 168 168: def javascript_tag(content, html_options = {}) 169: content_tag("script", javascript_cdata_section(content), html_options.merge(:type => "text/javascript")) 170: end
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 { $("details").visualEffect("toggle_blind"); $("more_link").update("Show me less"); } catch (e) { alert('RJS error:\n\n' + e.toString()); alert('$(\"details\").visualEffect(\"toggle_blind\"); \n$(\"more_link\").update(\"Show me less\");'); throw e }; return false;">Show me more</a>
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# File vendor/rails/actionpack/lib/action_view/helpers/javascript_helper.rb, line 82 82: def link_to_function(name, *args, &block) 83: html_options = args.last.is_a?(Hash) ? args.pop : {} 84: function = args[0] || '' 85: 86: html_options.symbolize_keys! 87: function = update_page(&block) if block_given? 88: content_tag( 89: "a", name, 90: html_options.merge({ 91: :href => html_options[:href] || "#", 92: :onclick => (html_options[:onclick] ? "#{html_options[:onclick]}; " : "") + "#{function}; return false;" 93: }) 94: ) 95: end
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# File vendor/rails/actionpack/lib/action_view/helpers/javascript_helper.rb, line 181 181: def array_or_string_for_javascript(option) 182: js_option = if option.kind_of?(Array) 183: "['#{option.join('\',\'')}']" 184: elsif !option.nil? 185: "'#{option}'" 186: end 187: js_option 188: end
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# File vendor/rails/actionpack/lib/action_view/helpers/javascript_helper.rb, line 177 177: def options_for_javascript(options) 178: '{' + options.map {|k, v| "#{k}:#{v}"}.sort.join(', ') + '}' 179: end