doctype -> StringRuby 4.0 で削除[permalink][rdoc][edit]-
HTML 4.01 Frameset の DOCTYPE 宣言を返します。
例require "cgi" cgi = CGI.new("html4Fr") p cgi.doctype # => "<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Frameset//EN\" \"http://www.w3.org/TR/html4/frameset.dtd\">"