Javascript 指定日期與現在時間相減

var strDate1 = "2000-10-25";
var now, s = "";
now = new Date();
now.setDate(now.getDate());
s += now.getYear()+"-";
s += (now.getMonth() + 101).toString().substring(1,3)+"-" ;
s += (now.getDate()+ 100).toString().substring(1,3) ;
strDate2 = s;
strDate1=strDate1.replace(/-/g,"/");
strDate2=strDate2.replace(/-/g,"/");
var date1 = Date.parse(strDate1);
var date2 = Date.parse(strDate2);
if (Math.ceil((date2-date1)/(24*60*60*1000))<=6573) { //未滿18
alert('你未满18岁');
}

這支Script可以在網頁檢查兩個日期是否相差18年整..