test if frames is defined

lib/single-file/processors/lazy/content/content-lazy-loader.js

@@ -86,9 +86,9 @@ this.singlefile.lib.processors.lazy.content.loader = this.singlefile.lib.process
 			}, options.loadDeferredImagesMaxIdleTime * 1.2);
 			maxTimeoutId = await deferForceLazyLoadEnd(timeoutId, idleTimeoutId, maxTimeoutId, observer, options, cleanupAndResolve);
 			observer.observe(document, { subtree: true, childList: true, attributes: true });
-			addEventListener.call(window, frames.LOAD_IMAGE_EVENT, onImageLoadEvent);
-			addEventListener.call(window, frames.IMAGE_LOADED_EVENT, onImageLoadedEvent);
 			if (frames) {
+				addEventListener.call(window, frames.LOAD_IMAGE_EVENT, onImageLoadEvent);
+				addEventListener.call(window, frames.IMAGE_LOADED_EVENT, onImageLoadedEvent);
 				frames.loadDeferredImagesStart(options);
 			}
 
@@ -110,8 +110,10 @@ this.singlefile.lib.processors.lazy.content.loader = this.singlefile.lib.process
 
 			function cleanupAndResolve(value) {
 				observer.disconnect();
-				removeEventListener.call(window, frames.LOAD_IMAGE_EVENT, onImageLoadEvent);
-				removeEventListener.call(window, frames.IMAGE_LOADED_EVENT, onImageLoadedEvent);
+				if (frames) {
+					removeEventListener.call(window, frames.LOAD_IMAGE_EVENT, onImageLoadEvent);
+					removeEventListener.call(window, frames.IMAGE_LOADED_EVENT, onImageLoadedEvent);
+				}
 				resolve(value);
 			}
 		});