diff --git a/layout/base/crashtests/399365-1.html b/layout/base/crashtests/399365-1.html
new file mode 100644
index 00000000000..ab5f2d0214f
--- /dev/null
+++ b/layout/base/crashtests/399365-1.html
@@ -0,0 +1,16 @@
+<html>
+<head>
+<script>
+function boom()
+{
+  document.body.insertBefore(document.createTextNode("y"), document.body.firstChild);
+}
+</script>
+</head>
+
+<body style="white-space: pre; direction: rtl;" onload="boom();">
+e
+0
+ </body>
+
+</html>
diff --git a/layout/base/crashtests/crashtests.list b/layout/base/crashtests/crashtests.list
index 83e6267b1fd..d20475d4868 100644
--- a/layout/base/crashtests/crashtests.list
+++ b/layout/base/crashtests/crashtests.list
@@ -29,6 +29,7 @@ load 379920-1.svg
 load 379920-2.svg
 load 397011-1.xhtml
 load 399132-1.xhtml
+load 399365-1.html
 load 399687-1.html
 load 403175-1.html
 load 403245-1.html
