refactored code and added win/lose popups

src/js/popup.js

@@ -46,7 +46,7 @@ class Popup {
 		this.content.push(objToDom({[Popup.STRONG]: cnt}));
 	}
 
-	async display() {
+	async display(parent=document.body) {
 		let outer=document.createElement('div');
 		outer.classList.add('popup');
 		let popup=outer.appendChild(document.createElement('div'));
@@ -67,7 +67,7 @@ class Popup {
 		});
 		buttons.forEach(btn => buttonSection.appendChild(btn));
 
-		document.body.appendChild(outer);
+		parent.appendChild(outer);
 
 		const code=await Promise.race(buttons.map(btn => new Promise(ok => {
 			btn.addEventListener('click', e => {
@@ -76,7 +76,7 @@ class Popup {
 			});
 		})));
 
-		document.body.removeChild(outer);
+		parent.removeChild(outer);
 		return code;
 	}
 }