//make all lower case for folder name
var agent=navigator.userAgent.toLowerCase();

//alert(agent);
var is_iphone = (agent.indexOf('iphone')!=-1);
if (is_iphone) { location.href="mobile/"; }
var is_ipad = (agent.indexOf('ipad')!=-1);
if (is_ipad) { location.href="mobile/"; }
var is_blackberry = (agent.indexOf('blackberry')!=-1);
if (is_blackberry) { location.href="mobile/"; }