JavaScript 判断 Android 还是 iOS

Android

function android() {
    return /Android/i.test(navigator.userAgent)
}

iOS

function iOS() {
    return [
        'iPad Simulator',
        'iPhone Simulator',
        'iPod Simulator',
        'iPad',
        'iPhone',
        'iPod'
    ].includes(navigator.platform)
        // iPad on iOS 13 detection
        || (navigator.userAgent.includes("Mac") && "ontouchend" in document)
}

参考

StackOverflow: Detect if device is iOS