Update index.html

index.html

@@ -16,7 +16,7 @@
               <li> You don't need to answer every question in the same session. Feel free to start and stop when convenient! </li>
             </ul>
             <p> Use the <strong>same email</strong> each time to keep your progress on the questions tracked. Thanks again for participating! </p>
-            <input type="text" id="email" />
+            <input type="text" id="email" placeholder="Email"/>
             <br /> <br />
             <button id="submit">Let's go!</button>
 		</div>