module ActionView::Helpers::TagHelper

Provides methods to generate HTML tags programmatically when you can't use a Builder. By default, they output XHTML compliant tags.

Constants

BOOLEAN_ATTRIBUTES
PRE_CONTENT_STRINGS
TAG_PREFIXES

Public Instance Methods

cdata_section(content) click to toggle source

Returns a CDATA section with the given content. CDATA sections are used to escape blocks of text containing characters which would otherwise be recognized as markup. CDATA sections begin with the string <![CDATA[ and end with (and may not contain) the string ]]>.

cdata_section("<hello world>")
# => <![CDATA[<hello world>]]>

cdata_section(File.read("hello_world.txt"))
# => <![CDATA[<hello from a text file]]>

cdata_section("hello]]>world")
# => <![CDATA[hello]]]]><![CDATA[>world]]>
# File lib/action_view/helpers/tag_helper.rb, line 126
def cdata_section(content)
  splitted = content.to_s.gsub(/\]\]\>/, ']]]]><![CDATA[>')
  "<![CDATA[#{splitted}]]>".html_safe
end
content_tag(name, content_or_options_with_block = nil, options = nil, escape = true, &block) click to toggle source

Returns an HTML block tag of type name surrounding the content. Add HTML attributes by passing an attributes hash to options. Instead of passing the content as an argument, you can also use a block in which case, you pass your options as the second parameter. Set escape to false to disable attribute value escaping.

Options

The options hash can be used with attributes with no value like (disabled and readonly), which you can give a value of true in the options hash. You can use symbols or strings for the attribute names.

Examples

content_tag(:p, "Hello world!")
 # => <p>Hello world!</p>
content_tag(:div, content_tag(:p, "Hello world!"), class: "strong")
 # => <div class="strong"><p>Hello world!</p></div>
content_tag(:div, "Hello world!", class: ["strong", "highlight"])
 # => <div class="strong highlight">Hello world!</div>
content_tag("select", options, multiple: true)
 # => <select multiple="multiple">...options...</select>

<%= content_tag :div, class: "strong" do -%>
  Hello world!
<% end -%>
 # => <div class="strong">Hello world!</div>
# File lib/action_view/helpers/tag_helper.rb, line 104
def content_tag(name, content_or_options_with_block = nil, options = nil, escape = true, &block)
  if block_given?
    options = content_or_options_with_block if content_or_options_with_block.is_a?(Hash)
    content_tag_string(name, capture(&block), options, escape)
  else
    content_tag_string(name, content_or_options_with_block, options, escape)
  end
end
escape_once(html) click to toggle source

Returns an escaped version of html without affecting existing escaped entities.

escape_once("1 < 2 &amp; 3")
# => "1 &lt; 2 &amp; 3"

escape_once("&lt;&lt; Accept & Checkout")
# => "&lt;&lt; Accept &amp; Checkout"
# File lib/action_view/helpers/tag_helper.rb, line 138
def escape_once(html)
  ERB::Util.html_escape_once(html)
end
tag(name, options = nil, open = false, escape = true) click to toggle source

Returns an empty HTML tag of type name which by default is XHTML compliant. Set open to true to create an open tag compatible with HTML 4.0 and below. Add HTML attributes by passing an attributes hash to options. Set escape to false to disable attribute value escaping.

Options

You can use symbols or strings for the attribute names.

Use true with boolean attributes that can render with no value, like disabled and readonly.

HTML5 data-* attributes can be set with a single data key pointing to a hash of sub-attributes.

To play nicely with JavaScript conventions sub-attributes are dasherized. For example, a key user_id would render as data-user-id and thus accessed as dataset.userId.

Values are encoded to JSON, with the exception of strings, symbols and BigDecimals. This may come in handy when using jQuery's HTML5-aware .data() from 1.4.3.

Examples

tag("br")
# => <br />

tag("br", nil, true)
# => <br>

tag("input", type: 'text', disabled: true)
# => <input type="text" disabled="disabled" />

tag("input", type: 'text', class: ["strong", "highlight"])
# => <input class="strong highlight" type="text" />

tag("img", src: "open & shut.png")
# => <img src="open &amp; shut.png" />

tag("img", {src: "open &amp; shut.png"}, false, false)
# => <img src="open &amp; shut.png" />

tag("div", data: {name: 'Stephen', city_state: %w(Chicago IL)})
# => <div data-name="Stephen" data-city-state="[&quot;Chicago&quot;,&quot;IL&quot;]" />
# File lib/action_view/helpers/tag_helper.rb, line 75
def tag(name, options = nil, open = false, escape = true)
  "<#{name}#{tag_options(options, escape) if options}#{open ? ">" : " />"}".html_safe
end

Private Instance Methods

boolean_tag_option(key) click to toggle source
# File lib/action_view/helpers/tag_helper.rb, line 182
def boolean_tag_option(key)
  %Q(#{key}="#{key}")
end
content_tag_string(name, content, options, escape = true) click to toggle source
# File lib/action_view/helpers/tag_helper.rb, line 144
def content_tag_string(name, content, options, escape = true)
  tag_options = tag_options(options, escape) if options
  content     = ERB::Util.unwrapped_html_escape(content) if escape
  "<#{name}#{tag_options}>#{PRE_CONTENT_STRINGS[name]}#{content}</#{name}>".html_safe
end
prefix_tag_option(prefix, key, value, escape) click to toggle source
# File lib/action_view/helpers/tag_helper.rb, line 174
def prefix_tag_option(prefix, key, value, escape)
  key = "#{prefix}-#{key.to_s.dasherize}"
  unless value.is_a?(String) || value.is_a?(Symbol) || value.is_a?(BigDecimal)
    value = value.to_json
  end
  tag_option(key, value, escape)
end
tag_option(key, value, escape) click to toggle source
# File lib/action_view/helpers/tag_helper.rb, line 186
def tag_option(key, value, escape)
  if value.is_a?(Array)
    value = escape ? safe_join(value, " ".freeze) : value.join(" ".freeze)
  else
    value = escape ? ERB::Util.unwrapped_html_escape(value) : value.to_s
  end
  %Q(#{key}="#{value.gsub('"'.freeze, '&quot;'.freeze)}")
end
tag_options(options, escape = true) click to toggle source
# File lib/action_view/helpers/tag_helper.rb, line 150
def tag_options(options, escape = true)
  return if options.blank?
  output = ""
  sep    = " ".freeze
  options.each_pair do |key, value|
    if TAG_PREFIXES.include?(key) && value.is_a?(Hash)
      value.each_pair do |k, v|
        next if v.nil?
        output << sep
        output << prefix_tag_option(key, k, v, escape)
      end
    elsif BOOLEAN_ATTRIBUTES.include?(key)
      if value
        output << sep
        output << boolean_tag_option(key)
      end
    elsif !value.nil?
      output << sep
      output << tag_option(key, value, escape)
    end
  end
  output unless output.empty?
end