diff --git a/layout/_third-party/math/mathjax.swig b/layout/_third-party/math/mathjax.swig
index f695c1a530..47cb650e00 100644
--- a/layout/_third-party/math/mathjax.swig
+++ b/layout/_third-party/math/mathjax.swig
@@ -18,22 +18,29 @@
       }
     }
   });
+
   MathJax.Hub.Register.StartupHook('TeX Jax Ready', function() {
     MathJax.InputJax.TeX.prefilterHooks.Add(function(data) {
       if (data.display) {
         var next = data.script.nextSibling;
-        while (next && next.nodeName.toLowerCase() === '#text') { next = next.nextSibling }
-        if (next && next.nodeName.toLowerCase() === 'br') { next.parentNode.removeChild(next) }
+        while (next && next.nodeName.toLowerCase() === '#text') {
+          next = next.nextSibling;
+        }
+        if (next && next.nodeName.toLowerCase() === 'br') {
+          next.parentNode.removeChild(next);
+        }
       }
     });
   });
-</script>
 
-<script type="text/x-mathjax-config">
   MathJax.Hub.Queue(function() {
     var all = MathJax.Hub.getAllJax(), i;
     for (i = 0; i < all.length; i += 1) {
-      document.getElementById(all[i].inputID + '-Frame').parentNode.className += ' has-jax';
+      element = document.getElementById(all[i].inputID + '-Frame').parentNode;
+      if (element.nodeName.toLowerCase() == 'li') {
+        element = element.parentNode;
+      }
+      element.classList.add('has-jax');
     }
   });
 </script>