tzoffset.php

<script language="JavaScript">

    var time = new Date()
    var cookieexpire = new Date(time.getTime() + 90 * 24 * 60 * 60 * 1000); //cookie expires in 90 days
    var timeclock = document.cookie;
    var timezone = (-(time.getTimezoneOffset()))

    function getthecookie(name) {
        var index = timeclock.indexOf(name + "=");
        if (index == -1) return null;
        index = timeclock.indexOf("=", index) + 1;
        var endstr = timeclock.indexOf(";", index);
        if (endstr == -1) endstr = timeclock.length;
        return unescape(timeclock.substring(index, endstr));
    }

    function setthecookie(timeclock, value) {
        if (value != null && value != "")
            document.cookie = timeclock + "=" + escape(value) + "; expires=" + cookieexpire.toGMTString();
        timeclock = document.cookie;
    }

    var tzoffset = getthecookie("tzoffset") || timezone;
    if (tzoffset == null || tzoffset == "")
        tzoffset = "0";
    setthecookie("tzoffset", tzoffset);
</script>