diff --git a/layout/generic/crashtests/397844-1.xhtml b/layout/generic/crashtests/397844-1.xhtml
new file mode 100644
index 000000000000..3ad9b8464b10
--- /dev/null
+++ b/layout/generic/crashtests/397844-1.xhtml
@@ -0,0 +1,55 @@
+<html xmlns="http://www.w3.org/1999/xhtml" class="reftest-wait">
+<head>
+
+<style type="text/css">
+.pad { padding: 3ch; }
+.fl:first-letter { }
+</style>
+
+
+<style id="s" type="text/css"></style>
+
+<script type="text/javascript">
+
+function boom()
+{
+  document.getElementById("td").nextSibling.splitText(11);
+  document.getElementById("td").style.padding = "11px";
+  
+  setTimeout(boom2, 10);
+}
+
+function boom2()
+{
+  document.body.style.counterReset = "chicken";
+  
+  setTimeout(boom3, 10);
+}
+
+function boom3()
+{
+  document.getElementById("s").textContent = "#xxx { }";
+  
+  setTimeout(boom4, 10);
+}
+
+function boom4()
+{
+  document.getElementById("td").style.padding = "";
+  setTimeout(boom5, 10);
+}
+
+function boom5()
+{
+  document.documentElement.removeAttribute("class");
+}
+
+</script>
+</head>
+
+<body style="width: 10em;" dir="rtl" onload="boom();">
+
+<div class="pad fl"><span><td class="pad fl" id="td"><span>abcd</span></td>ghi jklmnop 2 qrs tuvwxy</span></div>
+
+</body>
+</html>
diff --git a/layout/generic/crashtests/397844-2.xhtml b/layout/generic/crashtests/397844-2.xhtml
new file mode 100644
index 000000000000..d97600812c23
--- /dev/null
+++ b/layout/generic/crashtests/397844-2.xhtml
@@ -0,0 +1,55 @@
+<html xmlns="http://www.w3.org/1999/xhtml" class="reftest-wait">
+<head>
+
+<style type="text/css">
+.pad { padding: 3ch; }
+.fl:first-letter { }
+td { border: 1px solid green }
+</style>
+
+<style id="s" type="text/css"></style>
+
+<script type="text/javascript">
+
+function boom()
+{
+  document.getElementById("td").nextSibling.splitText(6);
+  document.getElementById("td").style.padding = "2px";
+  
+  setTimeout(boom2, 10);
+}
+
+function boom2()
+{
+  document.body.style.counterReset = "chicken";
+  
+  setTimeout(boom3, 10);
+}
+
+function boom3()
+{
+  document.getElementById("s").textContent = "#xxx { }";
+  
+  setTimeout(boom4, 10);
+}
+
+function boom4()
+{
+  document.getElementById("td").style.padding = "";
+  setTimeout(boom5, 10);
+}
+
+function boom5()
+{
+  document.documentElement.removeAttribute("class");
+}
+
+</script>
+</head>
+
+<body style="font-family: monospace; width: 14ch; border: 1px solid orange;" dir="rtl" onload="boom();">
+
+<div class="pad fl"><span><td class="pad fl" id="td"><span>abcd</span></td>ghi jk 2</span></div>
+
+</body>
+</html>
diff --git a/layout/generic/crashtests/crashtests.list b/layout/generic/crashtests/crashtests.list
index 3ec1d467f8d6..b0ad218d8e55 100644
--- a/layout/generic/crashtests/crashtests.list
+++ b/layout/generic/crashtests/crashtests.list
@@ -89,6 +89,8 @@ load 395316-1.html
 load 395450-1.xhtml
 load 397007-1.html
 load 397187-1.html
+load 397844-1.xhtml
+load 397844-2.xhtml
 load 397852-1.xhtml
 load 398181-1.html
 load 398181-2.html
