Fix path to js in examples/showalert.html

Author: Tray2

examples/showalert.html

@@ -49,6 +49,6 @@ <h1>Alert modal example</h1>
             <button onclick="hide('#alert-modal')">Close</button>
         </div>
     </section>
-    <script src="helper.js"></script>
+    <script src="./../helper.js"></script>
 </body>
 </html>