diff --git a/demo-performance.html b/demo-performance.html
index 7d0dd8e..ed669a6 100644
--- a/demo-performance.html
+++ b/demo-performance.html
@@ -137,9 +137,11 @@
   /************************************************************************/
 
   function restoreWithSpans() {
-    let spans = document.getElementsByClassName(highlightedWithSpanClass);
-    while(spans.length) {
-      let span = spans[0];
+    while (true) {
+      const span = document.querySelector(`.${highlightedWithSpanClass}`);
+      if (!span) {
+        break
+      }
       span.parentNode.insertBefore(span.firstChild, span);
       span.parentNode.removeChild(span);
     }
@@ -150,4 +152,4 @@
   }
 </script>
 </body>
-</html>
\ No newline at end of file
+</html>