js updates

step1-02/final/index.html

@@ -11,7 +11,7 @@
         <button class="submit">Add</button>
       </div>
       <nav class="filter">
-        <button class="active">all</button>
+        <button class="selected">all</button>
         <button>active</button>
         <button>completed</button>
       </nav>