Ruby String#to_json with support for html encoding and decoding

example.rb

# When inserting Javascript in HTML there is a a problem with the
# </script> end tag.
# 
# Standard Javascript escaping works fine for most strings, but the 
# browser interprets </script> before Javascript is being parsed, so 
# it needs to be HTML escaped while the browser is parsing, and then
# unescaped as Javascript parses it.

# Regular to_json
{ 'key' => '</script>' }.to_json
# => "{\"key\": \"</script>\"}"

# HTML escaped to_json with unescapeHTML() as the JS side decoder
{ 'key' => '</script>' }.to_json(:html_encode => 'unescapeHTML()')
# => "{\"key\": \"&lt;/script&gt;\".unescapeHTML()}"

string_ext.rb

class String
  def to_json_with_html_encoding(options = nil)
    if options.is_a?(Hash) && options[:html_encode]
      ERB::Util::h(self).to_json_without_html_encoding + '.' + options[:html_encode]
    else
      to_json_without_html_encoding
    end
  end
end

String.alias_method_chain :to_json, :html_encoding