Provides methods for linking a HTML page together with other assets, such as javascripts, stylesheets, and feeds.

Methods
Constants
JAVASCRIPT_DEFAULT_SOURCES = ['prototype', 'effects', 'dragdrop', 'controls'] unless const_defined?(:JAVASCRIPT_DEFAULT_SOURCES)
Public Class methods
register_javascript_include_default(*sources)

Register one or more additional JavaScript files to be included when 

  javascript_include_tag :defaults

is called. This method is intended to be called only from plugin initialization to register extra .js files the plugin installed in public/javascripts.

[ show source ]

    # File vendor/rails/actionpack/lib/action_view/helpers/asset_tag_helper.rb, line 80
80:       def self.register_javascript_include_default(*sources)
81:         @@javascript_default_sources.concat(sources)
82:       end
Public Instance methods
auto_discovery_link_tag(type = :rss, url_options = {}, tag_options = {})

Returns a link tag that browsers and news readers can use to auto-detect a RSS or ATOM feed for this page. The type can either be :rss (default) or :atom and the options follow the url_for style of declaring a link target.

Examples: 

  auto_discovery_link_tag # =>
    <link rel="alternate" type="application/rss+xml" title="RSS" href="http://www.curenthost.com/controller/action" />
  auto_discovery_link_tag(:atom) # =>
    <link rel="alternate" type="application/atom+xml" title="ATOM" href="http://www.curenthost.com/controller/action" />
  auto_discovery_link_tag(:rss, {:action => "feed"}) # =>
    <link rel="alternate" type="application/rss+xml" title="RSS" href="http://www.curenthost.com/controller/feed" />
  auto_discovery_link_tag(:rss, {:action => "feed"}, {:title => "My RSS"}) # =>
    <link rel="alternate" type="application/rss+xml" title="My RSS" href="http://www.curenthost.com/controller/feed" />

[ show source ]

    # File vendor/rails/actionpack/lib/action_view/helpers/asset_tag_helper.rb, line 21
21:       def auto_discovery_link_tag(type = :rss, url_options = {}, tag_options = {})
22:         tag(
23:           "link", 
24:           "rel"   => tag_options[:rel] || "alternate",
25:           "type"  => tag_options[:type] || "application/#{type}+xml",
26:           "title" => tag_options[:title] || type.to_s.upcase,
27:           "href"  => url_options.is_a?(Hash) ? url_for(url_options.merge(:only_path => false)) : url_options
28:         )
29:       end
image_path(source)

Returns path to an image asset. Example:

The src can be supplied as a…

  • full path, like "/my_images/image.gif"
  • file name, like "rss.gif", that gets expanded to "/images/rss.gif"
  • file name without extension, like "logo", that gets expanded to "/images/logo.png"

[ show source ]

     # File vendor/rails/actionpack/lib/action_view/helpers/asset_tag_helper.rb, line 120
120:       def image_path(source)
121:         compute_public_path(source, 'images', 'png')
122:       end
image_tag(source, options = {})

Returns an image tag converting the options into html options on the tag, but with these special cases:

  • :alt - If no alt text is given, the file name part of the src is used (capitalized and without the extension)
  • :size - Supplied as "XxY", so "30x45" becomes width="30" and height="45"

The src can be supplied as a…

  • full path, like "/my_images/image.gif"
  • file name, like "rss.gif", that gets expanded to "/images/rss.gif"
  • file name without extension, like "logo", that gets expanded to "/images/logo.png"

[ show source ]

     # File vendor/rails/actionpack/lib/action_view/helpers/asset_tag_helper.rb, line 133
133:       def image_tag(source, options = {})
134:         options.symbolize_keys
135:                 
136:         options[:src] = image_path(source)
137:         options[:alt] ||= File.basename(options[:src], '.*').split('.').first.capitalize
138:         
139:         if options[:size]
140:           options[:width], options[:height] = options[:size].split("x")
141:           options.delete :size
142:         end
143: 
144:         tag("img", options)
145:       end
javascript_include_tag(*sources)

Returns a script include tag per source given as argument. Examples: 

  javascript_include_tag "xmlhr" # =>
    <script type="text/javascript" src="/javascripts/xmlhr.js"></script>

  javascript_include_tag "common.javascript", "/elsewhere/cools" # =>
    <script type="text/javascript" src="/javascripts/common.javascript"></script>
    <script type="text/javascript" src="/elsewhere/cools.js"></script>

  javascript_include_tag :defaults # =>
    <script type="text/javascript" src="/javascripts/prototype.js"></script>
    <script type="text/javascript" src="/javascripts/effects.js"></script>
    ...
    <script type="text/javascript" src="/javascripts/application.js"></script> *see below

If there’s an application.js file in your public/javascripts directory, javascript_include_tag :defaults will automatically include it. This file facilitates the inclusion of small snippets of JavaScript code, along the lines of controllers/application.rb and helpers/application_helper.rb.

[ show source ]

    # File vendor/rails/actionpack/lib/action_view/helpers/asset_tag_helper.rb, line 60
60:       def javascript_include_tag(*sources)
61:         options = sources.last.is_a?(Hash) ? sources.pop.stringify_keys : { }
62:         if sources.first == :defaults
63:           sources = @@javascript_default_sources.dup
64:           if defined?(RAILS_ROOT) and File.exists?("#{RAILS_ROOT}/public/javascripts/application.js")
65:             sources << 'application' 
66:           end
67:         end
68:         sources.collect { |source|
69:           source = javascript_path(source)        
70:           content_tag("script", "", { "type" => "text/javascript", "src" => source }.merge(options))
71:         }.join("\n")
72:       end
javascript_path(source)

Returns path to a javascript asset. Example: 

  javascript_path "xmlhr" # => /javascripts/xmlhr.js

[ show source ]

    # File vendor/rails/actionpack/lib/action_view/helpers/asset_tag_helper.rb, line 34
34:       def javascript_path(source)
35:         compute_public_path(source, 'javascripts', 'js')        
36:       end
stylesheet_link_tag(*sources)

Returns a css link tag per source given as argument. Examples: 

  stylesheet_link_tag "style" # =>
    <link href="/stylesheets/style.css" media="screen" rel="Stylesheet" type="text/css" />

  stylesheet_link_tag "style", :media => "all" # =>
    <link href="/stylesheets/style.css" media="all" rel="Stylesheet" type="text/css" />

  stylesheet_link_tag "random.styles", "/css/stylish" # =>
    <link href="/stylesheets/random.styles" media="screen" rel="Stylesheet" type="text/css" />
    <link href="/css/stylish.css" media="screen" rel="Stylesheet" type="text/css" />

[ show source ]

     # File vendor/rails/actionpack/lib/action_view/helpers/asset_tag_helper.rb, line 106
106:       def stylesheet_link_tag(*sources)
107:         options = sources.last.is_a?(Hash) ? sources.pop.stringify_keys : { }
108:         sources.collect { |source|
109:           source = stylesheet_path(source)
110:           tag("link", { "rel" => "Stylesheet", "type" => "text/css", "media" => "screen", "href" => source }.merge(options))
111:         }.join("\n")
112:       end
stylesheet_path(source)

Returns path to a stylesheet asset. Example: 

  stylesheet_path "style" # => /stylesheets/style.css

[ show source ]

    # File vendor/rails/actionpack/lib/action_view/helpers/asset_tag_helper.rb, line 91
91:       def stylesheet_path(source)
92:         compute_public_path(source, 'stylesheets', 'css')
93:       end