js获取当天、前一天的日期

var time=(new Date).getTime()-24*60*60*1000;
var yesterday=new Date(time);
var month=yesterday.getMonth();
var day=yesterday.getDate();
yesterday=yesterday.getFullYear() + "-" + (yesterday.getMonth()> 9 ? (yesterday.getMonth() + 1) : "0" + (yesterday.getMonth() + 1)) + "-" +(yesterday.getDate()> 9 ? (yesterday.getDate()) : "0" + (yesterday.getDate()));

var myDate = new Date();     //获取当前年份(2位)
var year=myDate.getFullYear();    //获取完整的年份(4位,1970-????)
var month=myDate.getMonth();       //获取当前月份(0-11,0代表1月)
var day=myDate.getDate();        //获取当前日(1-31)
var dayNow=year+‘-‘+(month+1)+"-"+day;