convert timestamps

time

function toUserTimeZone(utc_date, offset){
    if (utc_date.slice(-3) !== "UTC") {
        utc_date += " UTC";
    }
    var local_date = new Date(utc_date);
    var local_offset = local_date.getTimezoneOffset() * 60000;
    var utc_time = local_date.getTime() + local_offset;
    return new Date(utc_time + (3600000 * offset));
}

var date_string = "2014/08/12 16:32:28";
var vet_date    = toUserTimeZone(date_string, -4.5);
var brt_date    = toUserTimeZone(date_string, -3);

console.log(vet_date); // Tue Aug 12 2014 12:02:28 GMT-0430 (VET)
console.log(brt_date); // Tue Aug 12 2014 13:32:28 GMT-0430 (VET)