function preloadImages()
{
    for(var i = 0; i < arguments.length; i++) {
        var img = new Image();
        img.src = arguments[i];
    }
}
function gregorianToLongCount()
{
    var y = document.f.y.value;
    if (document.f.era.value == "BCE") {
        y = -1 * y + 1;
    }
    var gd = new GregorianDate(y, document.f.m.value, document.f.d.value);
    var lc = gregorianDateToLongCountDate(gd);
    document.f.lc_baktun.value = lc.baktun;
    document.f.lc_katun.value = lc.katun;
    document.f.lc_tun.value = lc.tun;
    document.f.lc_winal.value = lc.winal;
    document.f.lc_kin.value = lc.kin;
    document.getElementById('baktun').src = 'images/maya_lc_' + lc.baktun + '.gif';
    document.getElementById('katun').src = 'images/maya_lc_' + lc.katun + '.gif';
    document.getElementById('tun').src = 'images/maya_lc_' + lc.tun + '.gif';
    document.getElementById('winal').src = 'images/maya_lc_' + lc.winal + '.gif';
    document.getElementById('kin').src = 'images/maya_lc_' + lc.kin + '.gif';
    calendarRound(lc);
}
function longCountToGregorian()
{
    var lc = new LongCountDate(document.f.lc_baktun.value, document.f.lc_katun.value, 
        document.f.lc_tun.value, document.f.lc_winal.value, document.f.lc_kin.value);
    //alert(lc.toString());
    var gd = longCountDateToGregorianDate(lc);
    var year = gd.year;
    var era = "CE";
    if (year < 1) {
        year = -1 * year + 1;
        era = "BCE";
    }
    document.f.y.value = year;
    document.f.m.value = gd.month;
    document.f.d.value = gd.day;
    document.f.era.value = era;
    calendarRound(lc);
}
function calendarRound(lc)
{
    var tzolkin = longCountToTzolkin(lc);
    var haab = longCountToHaab(lc);
    document.f.lc_tzolkin.value = tzolkin.trecena + " " + TZOLKIN_DAYS[tzolkin.veintena];
    document.f.lc_haab.value = haab.day + ' ' + HAAB_MONTHS[haab.month];
    document.getElementById('tz_t').src = 'images/maya_lc_' + tzolkin.trecena + '.gif';
    document.getElementById('ts_v').src = 'images/maya_ts_' + tzolkin.veintena + '.gif';
    document.getElementById('ha_d').src = 'images/maya_lc_' + haab.day + '.gif';
    document.getElementById('ha_m').src = 'images/maya_ha_' + haab.month + '.gif';
}
for(var i = 0; i < 20; i++) {
    preloadImages('images/maya_lc_' + i + '.gif');
}
preloadImages('images/maya_lc_kin.gif','images/maya_lc_winal.gif',
    'images/maya_lc_tun.gif','images/maya_lc_katun.gif','images/maya_lc_baktun.gif');

var old_onLoad = window.onload;
window.onload = function() {
    var today = new Date();
    document.f.y.value = today.getYear() + 1900;
    document.f.m.value = today.getMonth() + 1;
    document.f.d.value = today.getDate();
    document.f.era.value = 'CE';
    gregorianToLongCount();
    if (old_onLoad) {
        old_onLoad();
    }
}