怎么使用Javascript获取距今n天前的日期

怎么使用Javascript获取距今n天前的日期

　　复制代码 代码如下:

　　function Test(day) {

　　var today = new Date();

　　var beforMilliseconds = today.getTime() - 1000 * 3600 * 24 * day;

　　var beforday = new Date();

　　beforday.setTime(beforMilliseconds);

　　var strYear = beforday.getFullYear();

　　var strDay = beforday.getDate();

　　var strMonth = beforday.getMonth() + 1;

　　if (strMonth < 10) {

　　strMonth = "0" + strMonth;

　　}

　　var strYesterday = strYear + "-" + strMonth + "-" + strDay;

　　alert(strYesterday);

　　}