intro: Scroll to top when switching pages.

apps/intro.json

@@ -1,5 +1,5 @@
 {
 	"type": "tildefriends-app",
 	"emoji": "💡",
-	"previous": "&eN6DNPpQUNhGvxneLuLPgsOXR6qyFZ7u+MAz0b4fa7k=.sha256"
+	"previous": "&FGkkfFLaEID3V4lUjPbgCOwgEvNXkcVkzs0zzwD/gQ8=.sha256"
 }

apps/intro/index.html

@@ -34,6 +34,7 @@
 		class="w3-flex w3-dark-gray w3-center"
 	>
 		<div
+			id="scrollbox"
 			style="
 				flex: 1 1 auto;
 				overflow: auto;
@@ -251,6 +252,7 @@
 					index == 0 ? 'hidden' : 'visible';
 				document.getElementById('right').style.visibility =
 					index == slides.length - 1 ? 'hidden' : 'visible';
+				document.getElementById('scrollbox').scrollTo(0, 0);
 			}
 
 			let dots = [...document.getElementsByClassName('dot')];