get user time using timezone javascript

1function calcTime(city, offset) {
2    // create Date object for current location
3    var d = new Date();
4
5    // convert to msec
6    // subtract local time zone offset
7    // get UTC time in msec
8    var utc = d.getTime() + (d.getTimezoneOffset() * 60000);
9
10    // create new Date object for different city
11    // using supplied offset
12    var nd = new Date(utc + (3600000*offset));
13
14    // return time as a string
15    return "The local time for city"+ city +" is "+ nd.toLocaleString();
16}
17
18alert(calcTime('Bombay', '+5.5'));
19