Easily test whether your visitor is using a handheld device :
PF = navigator.platform; if (PF == null) PF = "Android";
UA = navigator.userAgent;
DEVICE = navigator.userAgent + " " + navigator.platform;
MOBILE = /PHONE|MOBILE|TABLET|IPOD|IPAD|BLACKBERRY|LUMIA|ANDROID|WEBOS|PLAYBOOK|BB10|MINI|CRMO|OPERA MINI|OPERA MOBI|PALM|WINDOWS CE|XOOM|SCH-I800|KINDLE/i.test(DEVICE) | 0;