js判断是电脑(pc)访问还是手机(mobile)访问

<script>
    if ((navigator.userAgent.match(/(iPhone|iPod|Android|ios|iOS|iPad|Backerry|WebOS|Symbian|Windows Phone|Phone)/i))) {
        document.write("手机访问.");
    }else{
        document.write("电脑访问.");
    }
</script>