define getter for scrollY on the window object

lib/lazy/web-lazy-loader-after.js

@@ -32,7 +32,7 @@
 		delete window._singleFile_timeoutScroll;
 		delete document.documentElement.scrollTop;
 		window.__defineGetter__("pageYOffset", () => document.documentElement.scrollTop);
-		document.documentElement.__defineGetter__("scrollY", () => document.documentElement.scrollTop);
+		window.__defineGetter__("scrollY", () => document.documentElement.scrollTop);
 		dispatchEvent(new UIEvent("scroll"));
 	}
 

lib/lazy/web-lazy-loader-before.js

@@ -42,7 +42,7 @@
 
 	function scroll(offsetY, maxOffsetY) {
 		document.documentElement.__defineGetter__("scrollTop", () => offsetY);
-		document.documentElement.__defineGetter__("scrollY", () => offsetY);
+		window.__defineGetter__("scrollY", () => offsetY);
 		window.__defineGetter__("pageYOffset", () => offsetY);
 		processScroll();