function $(id)
{
	return document.getElementById(id);
}

function gong_to_nong(SiteUrl)
{
	var year  = $('gyear').value;
	var month = $('gmonth').value;
	var day   = $('gday').value;

	if (year == '' || month == '' || day == '') {
		return false;
	}

	location.href = '/gongli/'+year+'-'+month+'-'+day+'.html';
}

function nong_to_gong(SiteUrl)
{
	var year  = $('nyear').value;
	var month = $('nmonth').value;
	var day   = $('nday').value;

	if (year == '' || month == '' || day == '') {
		return false;
	}

	location.href = '/nongli/'+year+'-'+month+'-'+day+'.html';
}

function leapYear(year)
{
    if (year % 4 == 0) {
        return true;
    }

    return false;
}

function getDays(year, month)
{
    var ar = new Array(12);
    ar[0]  = 31;
    ar[1]  = (leapYear(year)) ? 29 : 28;
    ar[2]  = 31;
    ar[3]  = 30;
    ar[4]  = 31;
    ar[5]  = 30;
    ar[6]  = 31;
    ar[7]  = 31;
    ar[8]  = 30;
    ar[9]  = 31;
    ar[10] = 30;
    ar[11] = 31;

    return ar[month];
}