From 3183eca200344322cd77c236d3aee2948d92ad7e Mon Sep 17 00:00:00 2001
From: "Davide P. Cervone" <dpvc@union.edu>
Date: Sun, 20 Mar 2016 11:48:12 -0400
Subject: [PATCH] Add checks to make sure that the math hasn't been removed
 from the page. (Resolves issue #1384.)

---
 unpacked/MathJax.js                 | 4 ++--
 unpacked/extensions/fast-preview.js | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/unpacked/MathJax.js b/unpacked/MathJax.js
index 117752453..2b4c1dc11 100644
--- a/unpacked/MathJax.js
+++ b/unpacked/MathJax.js
@@ -2182,7 +2182,7 @@ MathJax.Hub = {
         //
         //  Check if already processed or needs processing
         //
-        if (!script.MathJax || script.MathJax.state === STATE.PROCESSED) {state.i++; continue};
+        if (!script.parentNode || !script.MathJax || script.MathJax.state === STATE.PROCESSED) {state.i++; continue};
         if (!script.MathJax.elementJax || script.MathJax.state === STATE.UPDATE) {
           this.checkScriptSiblings(script);                 // remove preJax/postJax etc.
           var type = script.type.replace(/ *;(.|\s)*/,"");  // the input jax type
@@ -2286,7 +2286,7 @@ MathJax.Hub = {
         //  Check that there is an element jax
         //
         script = state.scripts[state.i];
-        if (!script || !script.MathJax || script.MathJax.error) {state.i++; continue}
+        if (!script || !script.parentNode || !script.MathJax || script.MathJax.error) {state.i++; continue}
         var jax = script.MathJax.elementJax; if (!jax) {state.i++; continue}
         //
         //  Call the output Jax's Process method (which will be its Translate()
diff --git a/unpacked/extensions/fast-preview.js b/unpacked/extensions/fast-preview.js
index 73f3ee43f..bc55d2a4b 100644
--- a/unpacked/extensions/fast-preview.js
+++ b/unpacked/extensions/fast-preview.js
@@ -100,7 +100,7 @@
     //  and call the PreviewHTML output jax to create the preview
     //
     Preview: function (data) {
-      if (!this.Active()) return;
+      if (!this.Active() || !data.script.parentNode) return;
       var preview = data.script.MathJax.preview || data.script.previousSibling;
       if (!preview || preview.className !== MathJax.Hub.config.preRemoveClass) {
         preview = HTML.Element("span",{className:MathJax.Hub.config.preRemoveClass});