diff --git a/dist/reader.html b/dist/reader.html
index db93957..c034cc3 100644
--- a/dist/reader.html
+++ b/dist/reader.html
@@ -6,7 +6,7 @@
 <title>Symcode Reader</title>
 <script>
 // https://bugs.webkit.org/show_bug.cgi?id=190800
-if (!'BigUint64Array' in window) {
+if (!('BigUint64Array' in window)) {
     window.BigUint64Array = Float64Array;
 }
 </script>
diff --git a/dist/writer.html b/dist/writer.html
index 9d195d4..28f16a2 100644
--- a/dist/writer.html
+++ b/dist/writer.html
@@ -6,7 +6,7 @@
 <title>Symcode Writer</title>
 <script>
 // https://bugs.webkit.org/show_bug.cgi?id=190800
-if (!'BigUint64Array' in window) {
+if (!('BigUint64Array' in window)) {
     window.BigUint64Array = Float64Array;
 }
 </script>