Apple seems to have removed this feature from iOS 9.
<link rel="apple-touch-icon" sizes="76x76" type="image/png" href="app/images/icons/novnc-76x76.png">
<link rel="apple-touch-icon" sizes="120x120" type="image/png" href="app/images/icons/novnc-120x120.png">
<link rel="apple-touch-icon" sizes="152x152" type="image/png" href="app/images/icons/novnc-152x152.png">
- <!-- App Start Image -->
- <link rel="apple-touch-startup-image" href="app/images/screen_320x460.png" />
-
<!-- Stylesheets -->
<link rel="stylesheet" href="app/styles/base.css" />