Automatic Timezone Detection Using JavaScript

jstz.js

var jstz = function() {
    var b = function(a) {
        a = -a.getTimezoneOffset();
        return null !== a ? a : 0
    }, c = function() {
        return b(new Date(2010, 0, 1, 0, 0, 0, 0))
    }, f = function() {
        return b(new Date(2010, 5, 1, 0, 0, 0, 0))
    }, e = function() {
        var a = c(),
            d = f(),
            b = c() - f();
        return new jstz.TimeZone(jstz.olson.timezones[0 > b ? a + ",1" : 0 < b ? d + ",1,s" : a + ",0"])
    };
    return {
        determine_timezone: function() {
            "undefined" !== typeof console && console.log("jstz.determine_timezone() is deprecated and will be removed in an upcoming version. Please use jstz.determine() instead.");
            return e()
        },
        determine: e,
        date_is_dst: function(a) {
            var d = 5 < a.getMonth() ? f() : c(),
                a = b(a);
            return 0 !== d - a
        }
    }
}();
jstz.TimeZone = function(b) {
    var c = null,
        c = b;
    "undefined" !== typeof jstz.olson.ambiguity_list[c] && function() {
        for (var b = jstz.olson.ambiguity_list[c], e = b.length, a = 0, d = b[0]; a < e; a += 1) if (d = b[a], jstz.date_is_dst(jstz.olson.dst_start_dates[d])) {
            c = d;
            break
        }
    }();
    return {
        name: function() {
            return c
        }
    }
};
jstz.olson = {};
jstz.olson.timezones = {
    "-720,0": "Etc/GMT+12",
    "-660,0": "Pacific/Pago_Pago",
    "-600,1": "America/Adak",
    "-600,0": "Pacific/Honolulu",
    "-570,0": "Pacific/Marquesas",
    "-540,0": "Pacific/Gambier",
    "-540,1": "America/Anchorage",
    "-480,1": "America/Los_Angeles",
    "-480,0": "Pacific/Pitcairn",
    "-420,0": "America/Phoenix",
    "-420,1": "America/Denver",
    "-360,0": "America/Guatemala",
    "-360,1": "America/Chicago",
    "-360,1,s": "Pacific/Easter",
    "-300,0": "America/Bogota",
    "-300,1": "America/New_York",
    "-270,0": "America/Caracas",
    "-240,1": "America/Halifax",
    "-240,0": "America/Santo_Domingo",
    "-240,1,s": "America/Asuncion",
    "-210,1": "America/St_Johns",
    "-180,1": "America/Godthab",
    "-180,0": "America/Argentina/Buenos_Aires",
    "-180,1,s": "America/Montevideo",
    "-120,0": "America/Noronha",
    "-120,1": "Etc/GMT+2",
    "-60,1": "Atlantic/Azores",
    "-60,0": "Atlantic/Cape_Verde",
    "0,0": "Etc/UTC",
    "0,1": "Europe/London",
    "60,1": "Europe/Berlin",
    "60,0": "Africa/Lagos",
    "60,1,s": "Africa/Windhoek",
    "120,1": "Asia/Beirut",
    "120,0": "Africa/Johannesburg",
    "180,1": "Europe/Moscow",
    "180,0": "Asia/Baghdad",
    "210,1": "Asia/Tehran",
    "240,0": "Asia/Dubai",
    "240,1": "Asia/Yerevan",
    "270,0": "Asia/Kabul",
    "300,1": "Asia/Yekaterinburg",
    "300,0": "Asia/Karachi",
    "330,0": "Asia/Kolkata",
    "345,0": "Asia/Kathmandu",
    "360,0": "Asia/Dhaka",
    "360,1": "Asia/Omsk",
    "390,0": "Asia/Rangoon",
    "420,1": "Asia/Krasnoyarsk",
    "420,0": "Asia/Jakarta",
    "480,0": "Asia/Shanghai",
    "480,1": "Asia/Irkutsk",
    "525,0": "Australia/Eucla",
    "525,1,s": "Australia/Eucla",
    "540,1": "Asia/Yakutsk",
    "540,0": "Asia/Tokyo",
    "570,0": "Australia/Darwin",
    "570,1,s": "Australia/Adelaide",
    "600,0": "Australia/Brisbane",
    "600,1": "Asia/Vladivostok",
    "600,1,s": "Australia/Sydney",
    "630,1,s": "Australia/Lord_Howe",
    "660,1": "Asia/Kamchatka",
    "660,0": "Pacific/Noumea",
    "690,0": "Pacific/Norfolk",
    "720,1,s": "Pacific/Auckland",
    "720,0": "Pacific/Tarawa",
    "765,1,s": "Pacific/Chatham",
    "780,0": "Pacific/Tongatapu",
    "780,1,s": "Pacific/Apia",
    "840,0": "Pacific/Kiritimati"
};
jstz.olson.dst_start_dates = {
    "America/Denver": new Date(2011, 2, 13, 3, 0, 0, 0),
    "America/Mazatlan": new Date(2011, 3, 3, 3, 0, 0, 0),
    "America/Chicago": new Date(2011, 2, 13, 3, 0, 0, 0),
    "America/Mexico_City": new Date(2011, 3, 3, 3, 0, 0, 0),
    "Atlantic/Stanley": new Date(2011, 8, 4, 7, 0, 0, 0),
    "America/Asuncion": new Date(2011, 9, 2, 3, 0, 0, 0),
    "America/Santiago": new Date(2011, 9, 9, 3, 0, 0, 0),
    "America/Campo_Grande": new Date(2011, 9, 16, 5, 0, 0, 0),
    "America/Montevideo": new Date(2011, 9, 2, 3, 0, 0, 0),
    "America/Sao_Paulo": new Date(2011, 9, 16, 5, 0, 0, 0),
    "America/Los_Angeles": new Date(2011,
    2, 13, 8, 0, 0, 0),
    "America/Santa_Isabel": new Date(2011, 3, 5, 8, 0, 0, 0),
    "America/Havana": new Date(2011, 2, 13, 2, 0, 0, 0),
    "America/New_York": new Date(2011, 2, 13, 7, 0, 0, 0),
    "Asia/Gaza": new Date(2011, 2, 26, 23, 0, 0, 0),
    "Asia/Beirut": new Date(2011, 2, 27, 1, 0, 0, 0),
    "Europe/Minsk": new Date(2011, 2, 27, 2, 0, 0, 0),
    "Europe/Helsinki": new Date(2011, 2, 27, 4, 0, 0, 0),
    "Europe/Istanbul": new Date(2011, 2, 28, 5, 0, 0, 0),
    "Asia/Damascus": new Date(2011, 3, 1, 2, 0, 0, 0),
    "Asia/Jerusalem": new Date(2011, 3, 1, 6, 0, 0, 0),
    "Africa/Cairo": new Date(2010, 3, 30, 4, 0, 0,
    0),
    "Asia/Yerevan": new Date(2011, 2, 27, 4, 0, 0, 0),
    "Asia/Baku": new Date(2011, 2, 27, 8, 0, 0, 0),
    "Pacific/Auckland": new Date(2011, 8, 26, 7, 0, 0, 0),
    "Pacific/Fiji": new Date(2010, 11, 29, 23, 0, 0, 0),
    "America/Halifax": new Date(2011, 2, 13, 6, 0, 0, 0),
    "America/Goose_Bay": new Date(2011, 2, 13, 2, 1, 0, 0),
    "America/Miquelon": new Date(2011, 2, 13, 5, 0, 0, 0),
    "America/Godthab": new Date(2011, 2, 27, 1, 0, 0, 0)
};
jstz.olson.ambiguity_list = {
    "America/Denver": ["America/Denver", "America/Mazatlan"],
    "America/Chicago": ["America/Chicago", "America/Mexico_City"],
    "America/Asuncion": ["Atlantic/Stanley", "America/Asuncion", "America/Santiago", "America/Campo_Grande"],
    "America/Montevideo": ["America/Montevideo", "America/Sao_Paulo"],
    "Asia/Beirut": "Asia/Gaza Asia/Beirut Europe/Minsk Europe/Helsinki Europe/Istanbul Asia/Damascus Asia/Jerusalem Africa/Cairo".split(" "),
    "Asia/Yerevan": ["Asia/Yerevan", "Asia/Baku"],
    "Pacific/Auckland": ["Pacific/Auckland", "Pacific/Fiji"],
    "America/Los_Angeles": ["America/Los_Angeles", "America/Santa_Isabel"],
    "America/New_York": ["America/Havana", "America/New_York"],
    "America/Halifax": ["America/Goose_Bay", "America/Halifax"],
    "America/Godthab": ["America/Miquelon", "America/Godthab"]
};

using.html

<script>
var timezone = jstz.determine();
consolo.log(timezone);
console.log(timezone.name()); 
//"Asia/Jakarta"
</script>