Clean up classes before exiting them

public/src/js/tutorial.js

@@ -1,17 +1,19 @@
-function Tutorial() {
-    var _this = this;
-
-    this.run = function() {
-        assets.sounds["bgm_setsume"].playLoop(0.1, false, 0, 1.054, 16.054)
-
-        $('#tutorial-end-button').click(function(){
-            assets.sounds["bgm_setsume"].stop();
-            assets.sounds["don"].play();
-
-            localStorage.setItem('tutorial', 'true');
-            new SongSelect();
-        });
-    };
-
-    $('#screen').load('/src/views/tutorial.html', _this.run);
-};
+class Tutorial{
+	constructor(){
+		loader.changePage("tutorial")
+		assets.sounds["bgm_setsume"].playLoop(0.1, false, 0, 1.054, 16.054)
+		this.endButton = document.getElementById("tutorial-end-button")
+		pageEvents.once(this.endButton, "click").then(this.onEnd.bind(this))
+	}
+	onEnd(){
+		this.clean()
+		assets.sounds["don"].play()
+		localStorage.setItem("tutorial", "true")
+		new SongSelect()
+	}
+	clean(){
+		assets.sounds["bgm_setsume"].stop()
+		pageEvents.remove(this.endButton, "click")
+		delete this.endButton
+	}
+}