module ERB::Util

def html_escape_once(s)

# => "<< Accept & Checkout"
html_escape_once('<< Accept & Checkout')

# => "1 < 2 & 3"
html_escape_once('1 < 2 & 3')

A utility method for escaping HTML without affecting existing escaped entities. 
def html_escape_once(s)
  result = s.to_s.gsub(HTML_ESCAPE_ONCE_REGEXP, HTML_ESCAPE)
  s.html_safe? ? result.html_safe : result
end