输入日期判断星期

<script type="text/javascript">
	function getMyDay(date){
		var week;
		if(date.getDay()==0){
			week="周日";
		}
		if(date.getDay()==1){
			week="周一";
		}
		if(date.getDay()==2){
			week="周二";
		}
		if(date.getDay()==3){
			week="周三";
		}
		if(date.getDay()==4){
			week="周四";
		}
		if(date.getDay()==5){
			week="周五";
		}
		if(date.getDay()==6){
			week="周六";
		}
		return alert(week);
	}
	var w1 = getMyDay(new Date("2000-4-27"));
</script>