Improve getNode() so that it doesn't find elements inside nodes that come from other MathML nodes (those with IDs). Resolves issue mathjax#1447.

Author: dpvc

unpacked/jax/output/CommonHTML/jax.js

@@ -336,34 +336,20 @@
     ucMatch: HTML.ucMatch,
     setScript: HTML.setScript,
 
-    getNodesByClass: (document.getElementsByClassName ? 
-      function (node,type) {return node.getElementsByClassName(type)} :
-      function (node,type) {
-        var NODES = [];
-        var nodes = node.getElementsByTagName("span");
-        var name = RegExp("\\b"+type+"\\b");
-        for (var i = 0, m = nodes.length; i < m; i++) {
-          if (name.test(nodes[i].className)) NODES.push = nodes[i];
-        }
-        return NODES;
-      }
-    ),
+    //
+    //  Look through the children of a node for one with the given type
+    //  but don't step into child nodes that are from MathML elements
+    //  themselves (they will have IDs).
+    //
     getNode: function (node,type) {
-      var nodes = this.getNodesByClass(node,type);
-      if (nodes.length === 1) return nodes[0];
-      var closest = nodes[0], N = this.getNodeDepth(node,closest);
-      for (var i = 1, m = nodes.length; i < m; i++) {
-        var n = this.getNodeDepth(node,nodes[i]);
-        if (n < N) {closest = nodes[i]; N = n}
+      var name = RegExp("\\b"+type+"\\b");
+      for (var i = 0, m = node.childNodes.length; i < m; i++) {
+        var child = node.childNodes[i];
+        if (name.test(child.className)) return child;
+        if (child.id == null) return this.getNode(child,type);
       }
-      return closest;
     },
-    getNodeDepth: function (parent,node) {
-      var n = 0;
-      while (node && node !== parent) {node = node.parentNode; n++}
-      return n;
-    },
-    
+
 
     /********************************************/