Action View JavaScript Helpers

Methods

Constants

JS_ESCAPE_MAP = { "\\" => "\\\\", "</" => '<\/', "\r\n" => '\n', "\n" => '\n', "\r" => '\n', '"' => '\\"', "'" => "\\'", "`" => "\\`", "$" => "\\$" }

Instance Public methods

escape_javascript(javascript)

Escapes carriage returns and single and double quotes for JavaScript segments.

Also available through the alias j(). This is particularly helpful in JavaScript responses, like:

$('some_element').replaceWith('<%= j render 'some/element_template' %>');
Also aliased as: j
📝 Source code 
# File actionview/lib/action_view/helpers/javascript_helper.rb, line 28
      def escape_javascript(javascript)
        javascript = javascript.to_s
        if javascript.empty?
          result = ""
        else
          result = javascript.gsub(/(\\|<\/|\r\n|\342\200\250|\342\200\251|[\n\r"']|[`]|[$])/u, JS_ESCAPE_MAP)
        end
        javascript.html_safe? ? result.html_safe : result
      end
🔎 See on GitHub

j(javascript)

Alias for: escape_javascript

javascript_tag(content_or_options_with_block = nil, html_options = {}, &block)

Returns a JavaScript tag with the content inside. Example:

javascript_tag "alert('All is good')"

Returns:

<script>
//<![CDATA[
alert('All is good')
//]]>
</script>

html_options may be a hash of attributes for the <script> tag.

javascript_tag "alert('All is good')", type: 'application/javascript'

Returns:

<script type="application/javascript">
//<![CDATA[
alert('All is good')
//]]>
</script>

Instead of passing the content as an argument, you can also use a block in which case, you pass your html_options as the first parameter.

<%= javascript_tag type: 'application/javascript' do -%>
  alert('All is good')
<% end -%>

If you have a content security policy enabled then you can add an automatic nonce value by passing nonce: true as part of html_options. Example:

<%= javascript_tag nonce: true do -%>
  alert('All is good')
<% end -%>
📝 Source code 
# File actionview/lib/action_view/helpers/javascript_helper.rb, line 75
      def javascript_tag(content_or_options_with_block = nil, html_options = {}, &block)
        content =
          if block_given?
            html_options = content_or_options_with_block if content_or_options_with_block.is_a?(Hash)
            capture(&block)
          else
            content_or_options_with_block
          end

        if html_options[:nonce] == true
          html_options[:nonce] = content_security_policy_nonce
        end

        content_tag("script", javascript_cdata_section(content), html_options)
      end
🔎 See on GitHub