Remove custom placeholder solution with standard HTML.

src/components/NoteList.vue

@@ -1,10 +1,10 @@
 <template>
   <textarea
     @keyup.enter="addNote"
-    onfocus="this.value=''"
-    onblur="this.value = 'Start typing something…'"
     v-model="content"
     rows="10"
+    placeholder="Start typing something…"
+    autofocus
   ></textarea>
   <div
     class="note"
@@ -25,8 +25,8 @@ export default {
         { id: 0, text: 'This is a note' },
         { id: 1, text: 'And another one.' }
       ],
-      content: 'Start typing something…',
-      current: null
+      current: null,
+      content: null
     }
   },
   methods: {