This gist is to redirect mobile apps to mobile theme.

script.js

function redirect(location) {
    var iframe = document.createElement('iframe');
    iframe.setAttribute('src', location);
    iframe.setAttribute('width', '1px');
    iframe.setAttribute('height', '1px');
    iframe.setAttribute('position', 'absolute');
    iframe.setAttribute('top', '0');
    iframe.setAttribute('left', '0');
    document.documentElement.appendChild(iframe);
    iframe.parentNode.removeChild(iframe);
    iframe = null;
};

redirect("custom-app://host");