Action View JavaScript Helpers¶ ↑

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' %>');

Source: | on GitHub

# File actionview/lib/action_view/helpers/javascript_helper.rb, line 30
def escape_javascript(javascript)
 javascript = javascript.to_s
 if javascript.empty?
 result = ""
 else
 result = javascript.gsub(/(\\|<\/|\r\n|342円200円250円|342円200円251円|[\n\r"']|[`]|[$])/u, JS_ESCAPE_MAP)
 end
 javascript.html_safe? ? result.html_safe : result
end

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: | on GitHub

# File actionview/lib/action_view/helpers/javascript_helper.rb, line 77
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.key?(:nonce) && auto_include_nonce)
 html_options[:nonce] = content_security_policy_nonce
 elsif html_options[:nonce] == false
 html_options.delete(:nonce)
 end
 content_tag("script", javascript_cdata_section(content), html_options)
end