diff --git a/layout/style/crashtests/1397363-1.html b/layout/style/crashtests/1397363-1.html
new file mode 100644
index 000000000000..5ccbfa31761c
--- /dev/null
+++ b/layout/style/crashtests/1397363-1.html
@@ -0,0 +1,13 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="UTF-8">
+<script>
+a = document.documentElement.animate([{ "clip": "rect(632vw,0,103.9vmax,5ex)" }],
+                                     { duration:96.2272536276,
+                                       iterations:Number.POSITIVE_INFINITY,
+                                       iterationComposite:"accumulate" });
+a.playbackRate = 3000;
+</script>
+</head>
+</html>
diff --git a/layout/style/crashtests/crashtests.list b/layout/style/crashtests/crashtests.list
index 52a3568a25a7..07b186d8f973 100644
--- a/layout/style/crashtests/crashtests.list
+++ b/layout/style/crashtests/crashtests.list
@@ -212,3 +212,4 @@ load 1393791.html
 load 1384232.html
 load 1395725.html
 load 1396041.html
+load 1397363-1.html
