detect IOS version upper or lower than 5

IOS Detection

function iOSversion() {
	if (/iP(hone|od|ad)/.test(navigator.platform)) {
		var v = (navigator.appVersion).match(/OS (\d+)_(\d+)_?(\d+)?/);
		return [parseInt(v[1], 10), parseInt(v[2], 10), parseInt(v[3] || 0, 10)];
	}
}

var ver = iOSversion();

if (ver && ver[0] <= 5) {
	console.log("ok, ios 5 or later");
}