I must have visited hundreds of pages trying to solve this problem but at last I stumbled on the solution.
In fact it was something quite simple. The action code is a conditional after testing for the device used: in the line:
if (/Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent)) {
It struck me that it may be better to test if it supported touch, so I added these lines before the conditional:
var isTouchSupported = 'ontouchstart' in window;
var startEvent = isTouchSupported ? 'touchstart' : 'mousedown';
var moveEvent = isTouchSupported ? 'touchmove' : 'mousemove';
var endEvent = isTouchSupported ? 'touchend' : 'mouseup';
and then replaced the conditional line with:
if (isTouchSupported) {
It worked like a charm - on my IMac, IPad, Iphone, Xperia Z1 (android) and Kindle Fire.
Peter Small