Attachment: HTML file contains exclusively Javascript

type.inbound
and any(attachments,
        (
          .file_extension in~ ("html", "htm", "shtml", "dhtml")
          or .file_extension in~ $file_extensions_common_archives
          or .file_type == "html"
        )
        and any(file.explode(.),
                length(.scan.strings.strings) == 1
                and any(.scan.strings.strings,
                        regex.imatch(., '\s{0,}<script.*')
                )
                and any(.scan.strings.strings,
                        strings.ends_with(., "</script>")
                )
        )
)