diff --git a/packages/phoenix-event-display/src/managers/url-options-manager.ts b/packages/phoenix-event-display/src/managers/url-options-manager.ts
index 74cb7e47..1a7d4fe7 100644
--- a/packages/phoenix-event-display/src/managers/url-options-manager.ts
+++ b/packages/phoenix-event-display/src/managers/url-options-manager.ts
@@ -32,8 +32,9 @@ export class URLOptionsManager {
     private eventDisplay: EventDisplay,
     private configuration: Configuration,
   ) {
+    const queryIndex = window.location.href.indexOf('?');
     this.urlOptions = new URLSearchParams(
-      window.location.href.substr(window.location.href.lastIndexOf('?')),
+      queryIndex !== -1 ? window.location.href.substring(queryIndex) : '',
     );
   }