Added minimal polyfill for IntersectionObserver

scripts/AnimeNotifier.ts

@@ -9,6 +9,9 @@ export class AnimeNotifier {
 
 	constructor(app: Application) {
 		this.app = app
+
+		if("IntersectionObserver" in window) {
+			// Enable lazy load
 			this.visibilityObserver = new IntersectionObserver(
 				entries => {
 					for(let entry of entries) {
@@ -20,6 +23,16 @@ export class AnimeNotifier {
 				},
 				{}
 			)
+		} else {
+			// Disable lazy load feature
+			this.visibilityObserver = {
+				disconnect: () => {},
+				observe: (elem: HTMLElement) => {
+					elem["became visible"]()
+				},
+				unobserve: (elem: HTMLElement) => {}
+			} as IntersectionObserver
+		}
 	}
 
 	onReadyStateChange() {