diff --git a/lib/experimental/modules/class-gutenberg-modules.php b/lib/experimental/modules/class-gutenberg-modules.php
index ebdc22e58e8b6..5aa012f8e2f2c 100644
--- a/lib/experimental/modules/class-gutenberg-modules.php
+++ b/lib/experimental/modules/class-gutenberg-modules.php
@@ -152,7 +152,7 @@ public static function print_module_preloads() {
 	 * import maps (https://github.com/guybedford/es-module-shims/issues/406).
 	 */
 	public static function print_import_map_polyfill() {
-		$test = 'HTMLScriptElement.supports?.("importmap")';
+		$test = 'HTMLScriptElement.supports && HTMLScriptElement.supports("importmap")';
 		$src  = gutenberg_url( '/build/modules/importmap-polyfill.min.js' );
 
 		echo (