如何通过javascript检测特定时区的日期和时间

Question

一个人向我建议

If you know the UTC offset then you can pass it and get the time using following function:

function calcTime(city, offset) {
    // create Date object for current location
    var d = new Date();

    // convert to msec
    // subtract local time zone offset
    // get UTC time in msec
    var utc = d.getTime() - (d.getTimezoneOffset() * 60000);

    // create new Date object for different city
    // using supplied offset
    var nd = new Date(utc + (3600000*offset));

    // return time as a string
    return "The local time for city"+ city +" is "+ nd.toLocaleString();
}

alert(calcTime('Bombay', '+5.5'));

但我知道用户的pc时区如＆＃34; Asia / Kolkata＆＃34;或者＆＃34;欧洲/伦敦＆＃34;那我怎么能使用任何js库获取日期和时间。 moment.js可以做到这一点，如果是，所以请给我一些moment.js相关代码，我将通过时区ID并获得该时区日期＆amp;时间。感谢