Use document.head when available, and look up scripts via namespace if not found without it. Resolves issue #1016.

Author: dpvc

unpacked/MathJax.js

@@ -641,7 +641,7 @@ MathJax.cdnFileVersions = {};       // can be used to specify revisions for indi
     if (document.styleSheets && document.styleSheets.length > sheets)
       {sheets = document.styleSheets.length}
     if (!head) {
-      head = (document.getElementsByTagName("head"))[0];
+      head = document.head || ((document.getElementsByTagName("head"))[0]);
       if (!head) {head = document.body}
     }
     return head;
@@ -3041,6 +3041,8 @@ MathJax.Hub.Startup = {
   var HEAD = document.getElementsByTagName("head")[0];
   if (!HEAD) {HEAD = document.childNodes[0]};
   var scripts = (document.documentElement || document).getElementsByTagName("script");
+  if (scripts.length === 0 && HEAD.namespaceURI)
+    scripts = document.getElementsByTagNameNS(HEAD.namespaceURI,"script");
   var namePattern = new RegExp("(^|/)"+BASENAME+"\\.js(\\?.*)?$");
   for (var i = scripts.length-1; i >= 0; i--) {
     if ((scripts[i].src||"").match(namePattern)) {