Merge pull request #21 from bkardell/master

Proposed changes for linking and tabindexing...


Merging this as I am pretty confident that no other class like this has a constructor and I'd rather be less special than more, and I'd like to do the follow on work that is waiting on this.

index.html

@@ -422,6 +422,10 @@ <h4>DOM and Javascript</h4>
             corresponding MathML
             <a href="#global-attributes">content attribute</a>.
           </p>
+          <p>
+            All of the nodes representing <a>MathML Hyperlink Elements</a> in the DOM must implement, and expose to scripts the following <dfn><code>MathMLLinkableElement</code></dfn> interface.
+          </p>
+          <pre class="idl" data-include="webidl/MathMLLinkableElement.idl"></pre>
         </section>
         <section id="text-layout">
           <h4>Text layout</h4>
@@ -452,9 +456,7 @@ <h4>Focus</h4>
               apply, as defined in that specification.
             </p>
             <p>
-              Any MathML elements containing an href attribute are valid links
-              and are focusable.  Their tabindex focus flag
-              must be set unless the user agent normally provides an alternative
+              All <code>MathMLLinkableElement</code> elements are potentially linkable with an <code>href</code> attribute.  Their default tabindex is <code>0</code>.  If their <code>href</code> contains a valid URL, their focus flag must be set unless the user agent normally provides an alternative
               method of keyboard traversal of links, and they appear in the
               sequential focus order.
             </p>
@@ -527,10 +529,12 @@ <h3>Global Attributes</h3>
           elements:
         </p>
         <ul>
+          <li><a>id</a></li>
+          <li><a>class</a></li>
+          <li><a><code>style</code></a></li>
           <li><a><code>data-*</code></a></li>
           <li><a><code>dir</code></a></li>
           <li><a><code>displaystyle</code></a></li>
-          <li><a><code>href</code></a></li>
           <li><a><code>mathbackground</code></a></li>
           <li><a><code>mathcolor</code></a></li>
           <li><a><code>mathsize</code></a></li>
@@ -791,6 +795,10 @@ <h3>The Top-Level <code>&lt;math&gt;</code> Element</h3>
           respectively.
         </div>
       </section>
+      <section id="linkable-math-elements">
+        <h3><dfn>MathML Hyperlink Elements</dfn></h3>
+        <p>All <a href="#token-elements">token elements</a> and the <a href="#horizontally-group-sub-expressions-mrow">mrow</a> grouping element are potentially linkable and may contain an <code>href</code> attribute.  They are the MathML equivalents of HTML's <a data-cite="html#the-a-element">a</a> and must follow all of the same criteria laid out for links there.</p>
+      </section>
     </section>
     <section class="normative">
       <h2>Presentation Markup</h2>

webidl/MathMLLinkableElement.idl

@@ -0,0 +1,16 @@
+[Exposed=Window]
+interface MathMLLinkableElement : MathMLElement { 
+  [CEReactions] attribute DOMString target;
+  [CEReactions] attribute DOMString download;
+  [CEReactions] attribute USVString ping;
+  [CEReactions] attribute DOMString rel;
+  [SameObject, PutForwards=value] readonly attribute DOMTokenList relList;
+  [CEReactions] attribute DOMString hreflang;
+  [CEReactions] attribute DOMString type;
+
+  [CEReactions] attribute DOMString text;
+
+  [CEReactions] attribute DOMString referrerPolicy;
+ };
+
+ MathMLElement includes HTMLHyperlinkElementUtils;