Detect iPhone 3G or 3GS (and iPod touch 2G vs iPod touch 3G) in JavaScript

Question

Does anyone know a way to detect the older set of devices:

• iPod touch 1G
• iPhone 2G
• iPhone 3G
• iPod touch 2G

From the newer

Answer 1

Little Benchmark that detects older models. The Benchmark takes 5-30ms so no real problem.

function runBenchmark(){
    var time,
    init = new Date(),
    iterations = 5000;
    while (iterations--) {
        Math.sqrt(iterations*Math.random());
    }
    time = new Date - init;
    return time;
}

function detectIphoneSpeed () {
    if (runBenchmark()<15) {
        return "3gs";
    } else {
        return "3g";
    }
}
var iphoneSpeed = detectIphoneSpeed();