calc43.pug

doctype html
html
  head
    meta( http-equiv="Content-Type" content="text/html; charset=UTF-8" )
    - var pageTitle = 'Complicated ways to write numbers'
    title= pageTitle
    meta( http-equiv="Content-Script-Type" content="text/javascript" )
  body.page.screen
    h2= pageTitle

    script.
      'use strict';
      console.log("42 + 1 =", ("<!CDATA[[ </script> ]]>" + ((+(0</script>/)
        < '<!-- derp -->'.length) && "<script><!CDATA[[]]>")).length);

    script
      :cdata
        'use strict';
        console.log("42 + 1 =", ("<!CDATA[[ </script> ]]>" + ((+(0</script>/)
          < '<!-- derp -->'.length) && "<script><!CDATA[[]]>")).length);

    script
      :cdata-js
        'use strict';
        console.log("42 + 1 =", ("<!CDATA[[ </script> ]]>" + ((+(0</script>/)
          < '<!-- derp -->'.length) && "<script><!CDATA[[]]>")).length);

    script
      :escape-html
        'use strict';
        console.log("42 + 1 =", ("<!CDATA[[ </script> ]]>" + ((+(0</script>/)
          < '<!-- derp -->'.length) && "<script><!CDATA[[]]>")).length);

nice html

The new one is even more evil. I hope pug can soon help me escape that properly!

PS: If anyone wonders why Firefox stops at </script> even though it's properly XML-escaped inside a CDATA section: Because that only applies to XML, not HTML.

Since the CDATA has no effect in HTML, updated to include a comment, too.