Update index.html (#3)

- Update index.html (f585d6070d554816f52da91cd7cf0fd00420f77b)

index.html

@@ -18,6 +18,6 @@
             <label><input id="animate" type="checkbox" checked="true"> 自轉/繞行示意</label>
           </div>
         </div>
-        <script src="index.js"/>
+        <script src="index.js"></script>
 	</body>
 </html>