This snippet of code can be used to determine any version of iOS 2.0 and later.
function iOSversion() {
if (/iP(hone|od|ad)/.test(navigator.platform)) {
// supports iOS 2.0 and later: <http://bit.ly/TJjs1V>
var v = (navigator.appVersion).match(/OS (\d+)_(\d+)_?(\d+)?/);
return [parseInt(v[1], 10), parseInt(v[2], 10), parseInt(v[3] || 0, 10)];
}
}
ver = iOSversion();
if (ver[0] >= 5) {
alert('This is running iOS 5 or later.');
}