计算两个日期相差的天数

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<button onClick="btnDayCount_Click();">计算相差天数</button>
<script type="text/javascript" > // language="JavaScript"
   function btnDayCount_Click(){
      // alert("计算相差天数");
       var day1 = "2002-1-10" ;
       var day2 = "2002-10-10" ;
       alert(DateDiff(day1,day2)) ;
   }

   //计算天数差的函数，通用
   function DateDiff(sDate1, sDate2){    //sDate1和sDate2是2002-12-18格式
       var aDate, oDate1, oDate2, iDays ;
       aDate = sDate1.split("-") ;
      /* for (var i = 0; i < aDate.length; i++) {
          alert(aDate[i]);
   } */
       oDate1 = new Date(aDate[1] + '-' + aDate[2] + '-' + aDate[0]) ;   //转换为12-18-2002格式
       aDate = sDate2.split("-") ;
       oDate2 = new Date(aDate[1] + '-' + aDate[2] + '-' + aDate[0]) ;
       //Math.abs(num)求出绝对值
       //parseInt(num)解析字符串，返回一个整数
       iDays = parseInt(Math.abs(oDate1 - oDate2) / 1000 / 60 / 60 /24) ; //把相差的毫秒数转换为天数
       return iDays;
}
</script>
</body>
</html>