<!DOCTYPE html>
<html>
<head>
<title>My App</title>
</head>
<body>
<script>
var isAndroid = /(android)/i.test(navigator.userAgent);
var isiOS = /(iphone|ipad)/i.test(navigator.userAgent);
if (isAndroid) {
window.location.href = "https://play.google.com/store/apps/my-app";
} else if (isiOS) {
window.location.href = "https://itunes.apple.com/us/app/my-app/idXXXXXXXXX";
}
</script>
</body>
</html>