fix validation failure

examples/dashboard/index.html

@@ -46,7 +46,7 @@
             <li><a href="#">Profile</a></li>
             <li><a href="#">Help</a></li>
           </ul>
-          <form action="" class="navbar-form navbar-right">
+          <form class="navbar-form navbar-right">
             <input type="text" class="form-control" placeholder="Search...">
           </form>
         </div>