diff --git a/webstead.xhtml b/webstead.xhtml
index 8188f78..f0df386 100644
--- a/webstead.xhtml
+++ b/webstead.xhtml
@@ -43,6 +43,7 @@
          https://issues.chromium.org/issues/40518469
          And it's not a module because Safari can't handle that. -->
     <script async="async"><![CDATA[
+    "use strict";
     var Bedstead;
     function update_glyph(c_update_needed) {
         var args = [];
@@ -74,12 +75,12 @@
         });
     }
     function from_c(c) {
-        re = /[0-7]+/g;
+        var re = /[0-7]+/g;
         document.querySelector('#inpane').reset();
-        for (row of document.querySelector('#pixels').rows) {
-            match = re.exec(c);
+        for (var row of document.querySelector('#pixels').rows) {
+            var match = re.exec(c);
             if (match == null) break;
-            rowbits = Number.parseInt(match[0], 8);
+            var rowbits = Number.parseInt(match[0], 8);
             for (var pixel
                  of Array.from(row.querySelectorAll('input')).reverse()) {
                 pixel.checked = (rowbits & 1 != 0);