Several attributes for paypal and GooglePlus were defined in local dtd but local dtd now breaks W3C validation? W3C validation?

问题

Since 2007, we have used a local DTD to add a tag-pair and to define several attributes for PayPlal and google++. This is the local DTD...

<!ELEMENT havindex EMPTY>
<!ATTLIST havindex id CDATA #REQUIRED>
<!ENTITY % head.misc "(script|style|meta|link|object|isindex|havindex)*">
<!ENTITY % html.transitional PUBLIC
  "-//W3C//DTD XHTML 1.0 Transitional//EN"
  "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<!-- =========== 3 div attributes for googleplus share button ====== -->
<!ATTLIST div data-action       CDATA #IMPLIED>
<!ATTLIST div data-annotation   CDATA #IMPLIED>
<!ATTLIST div data-height       CDATA #IMPLIED>
<!ATTLIST div data-id           CDATA #IMPLIED>
<!-- =========== 2 script attributes for paypal support ========== -->
<!ATTLIST script data-pp-pubid          CDATA #IMPLIED>
<!ATTLIST script data-pp-placementtype  CDATA #IMPLIED>
%html.transitional;

... We recently converted the site to https (not sure that has anything to do with it, but just as an aside) and all of a sudden, it seems that the local DTD breaks the W3C validation - it fails immediately on the DTD. When I use a standard DTD, of course, the new tag and attributes are seen as validation errors. Any thoughts on how to use the local dtd or to define the attributes, at least?

来源：https://stackoverflow.com/questions/48956393/several-attributes-for-paypal-and-googleplus-were-defined-in-local-dtd-but-local