gistfile1.rb

# remove content of script tags using Sanitize 
require 'sanitize'

html = '<p>Do not<script>fail();</script> kill the <a href="/cats/42">cat</a>.</p>'

Sanitize.clean(html, Sanitize::Config::BASIC.merge(
  :transformers => lambda { |env|
    node = env[:node]
    return unless node.name.downcase == 'script'
    node.children.each(&:remove)
    { :node => node }
  }
))

# => "<p>Do not kill the <a href=\"/cat/42\" rel=\"nofollow\">cat</a>.</p>"