var curTime = new Date();                   //获取当前时间

var oneTime =  1000*24*60*60;

var beforeTime = new Date(curTime - oneTime*7);        //获取上星期时间

var beforeTime_1 = new Date(curTime - oneTime*(curTime.getDay()+6);    //获取上周一时间。

var beforeMonthLast = new Date(curTime - curTime.getDate()*oneTime);     //获取上个月最后一天

var  beforeMonth_1 = new Date(curTime - (beforeMonthLast.getDate()-1)*oneTime);       //获取上个月1号时间

console.log(curTime);

console.log(beforeTime);

console.log(beforeTime_1);

console.log(beforeMonthLast);

console.log(beforeMonth_1);