function countdown(){
		calendar = new Date();
		day = calendar.getDay();
		month = calendar.getMonth();
		date = calendar.getDate();
		year = calendar.getYear();
		if (year< 100) year = 1900 + year;
		cent = parseInt(year/100);
		g = year % 19;
		k = parseInt((cent - 17)/25);
		i = (cent - parseInt(cent/4) - parseInt((cent - k)/3) + 19*g + 15) % 30;
		i = i - parseInt(i/28)*(1 - parseInt(i/28)*parseInt(29/(i+1))*parseInt((21-g)/11));
		j = (year + parseInt(year/4) + i + 2 - cent + parseInt(cent/4)) % 7;
		l = i - j;
		emonth = 3 + parseInt((l + 40)/44);
		edate = l + 28 - 31*parseInt((emonth/4));
		emonth--;
		var dayname = new Array ("星期日", "星期一", "星期二", "星期三", "星期四", "星期五", "星期六");
		var monthname =
		new Array ("1月","2月","3月","4月","5月","6月","7月","8月","9月","10月","11月","12月" );
		var time="今天是：<font style=font-size:9pt>"+year +"年"+monthname[month]+date + "日&nbsp;"+dayname[day]+" "+"</span></font>";
		var holiday="";
		if ((month == 0) && (date == 1)) holiday="&nbsp;<font style=font-size:9pt color=red>元旦节";
		if ((month == 2) && (date == 8)) holiday="&nbsp;<font style=font-size:9pt color=red>妇女节";
		if ((month == 3) && (date == 1)) holiday="&nbsp;<font style=font-size:9pt color=red>愚人节";
		if ((month == 4) && (date == 1)) holiday="&nbsp;<font style=font-size:9pt color=red>国际劳动节";
		if ((month == 4) && (date == 4)) holiday="&nbsp;<font style=font-size:9pt color=red>青年节";
		if ((month == 4) && (date == 12)) holiday="&nbsp;<font style=font-size:9pt color=red>护士节";
		if ((month == 4) && (date == 15)) holiday="&nbsp;<font style=font-size:9pt color=red>全国助残日";
		if ((month == 4) && (date == 31)) holiday="&nbsp;<font style=font-size:9pt color=red>世界无烟日";
		if ((month == 5) && (date == 1)) holiday="&nbsp;<font style=font-size:9pt color=red>国际儿童节";
		if ((month == 5) && (date == 5)) holiday="&nbsp;<font style=font-size:9pt color=red>世界环境日";
		if ((month == 5) && (date == 19)) holiday="&nbsp;<font style=font-size:9pt color=red>端午节";		
		if ((month == 5) && (date == 17)) holiday="&nbsp;<font style=font-size:9pt color=red>父亲节";
		if ((month == 5) && (date == 23)) holiday="&nbsp;<font style=font-size:9pt color=red>国际奥林匹克日";
		if ((month == 5) && (date == 26)) holiday="&nbsp;<font style=font-size:9pt color=red>国际反毒品日";
		if ((month == 6) && (date == 1)) holiday="&nbsp;<font style=font-size:9pt color=red>香港回归纪念日";
		if ((month == 6) && (date == 7)) holiday="&nbsp;<font style=font-size:9pt color=red>抗日战争纪念日";
		if ((month == 6) && (date == 11)) holiday="&nbsp;<font style=font-size:9pt color=red>世界人口日";
		if ((month == 7) && (date == 11)) holiday="&nbsp;<font style=font-size:9pt color=red>七夕情人节";
		if ((month == 8) && (date == 8)) holiday="&nbsp;<font style=font-size:9pt color=red>国际扫盲日";
		if ((month == 8) && (date == 10)) holiday="&nbsp;<font style=font-size:9pt color=red>教师节";
		if ((month == 8) && (date == 17)) holiday="&nbsp;<font style=font-size:9pt color=red>国际和平日";
		if ((month == 8) && (date == 25)) holiday="&nbsp;<font style=font-size:9pt color=red>中秋节";
		if ((month == 9) && (date == 1)) holiday="&nbsp;<font style=font-size:9pt color=red>国庆节";
		if ((month == 9) && (date == 6)) holiday="&nbsp;<font style=font-size:9pt color=red>老人节";	
		if ((month == 9) && (date == 11)) holiday="&nbsp;<font style=font-size:9pt color=red>重阳节";
		if ((month == 9) && (date == 15)) holiday="&nbsp;<font style=font-size:9pt color=red>国际盲人节";	
		if ((month == 9) && (date == 16)) holiday="&nbsp;<font style=font-size:9pt color=red>世界粮食日";		
		if ((month == 9) && (date == 24)) holiday="&nbsp;<font style=font-size:9pt color=red>联合国日";	
		if ((month == 10) && (date == 14)) holiday="&nbsp;<font style=font-size:9pt color=red>世界糖尿病日";
		if ((month == 10) && (date == 17)) holiday="&nbsp;<font style=font-size:9pt color=red>国际大学生节";
		if ((month == 11) && (date == 1)) holiday="&nbsp;<font style=font-size:9pt color=red>世界艾滋病日";
		if ((month == 11) && (date == 3)) holiday="&nbsp;<font style=font-size:9pt color=red>世界残疾人日";
		if ((month == 11) && (date == 9)) holiday="&nbsp;<font style=font-size:9pt color=red>世界足球日";
		if ((month == 11) && (date == 20)) holiday="&nbsp;<font style=font-size:9pt color=red>澳门回归纪念日";
		if ((month == 11) && (date == 25)) holiday="&nbsp;<font style=font-size:9pt color=red>圣诞节";
		time=time+holiday+"<br></span></font>";
		clock.innerHTML=time;
		}