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function calculate_time_zone() {
    var rightNow = new Date();
    var jan1 = new Date(rightNow.getFullYear(), 0, 1, 0, 0, 0, 0);  // jan 1st
    var june1 = new Date(rightNow.getFullYear(), 6, 1, 0, 0, 0, 0); // june 1st
    var temp = jan1.toGMTString();
    var jan2 = new Date(temp.substring(0, temp.lastIndexOf(" ")-1));
    temp = june1.toGMTString();
    var june2 = new Date(temp.substring(0, temp.lastIndexOf(" ")-1));
    var std_time_offset = (jan1 - jan2) / (1000 * 60 * 60);
    var daylight_time_offset = (june1 - june2) / (1000 * 60 * 60);
    var dst;
    if (std_time_offset == daylight_time_offset) {
        dst = "0"; // daylight savings time is NOT observed
    } else {
        // positive is southern, negative is northern hemisphere
        var hemisphere = std_time_offset - daylight_time_offset;
        if (hemisphere >= 0)
            std_time_offset = daylight_time_offset;
        dst = "1"; // daylight savings time is observed
    }
    return std_time_offset;
}