获取指定日期前7天时间（近7天）

//日期格式化
function dateFormat(date){ //date为中国标准时间:例 new Date()结果的格式
  var year = date.getFullYear().toString();
  var month = date.getMonth() + 1;
  if(month<10) {
    month = "0" + month.toString();
  } else {
   month = month.toString();
  }
  var day = date.getDate();
  if(day <10) {
    day = "0" + day .toString();
  } else {
   day = day .toString();
  }
  return year + month + day; //返回格式为20190615
}
//获取近七天日期
function getRencentlySevenDay(tarDay){ //date为中国标准时间:例 new Date()结果的格式
  var tarDay1=dateFormat(new Date(tarDay.getTime()-(0*24*60*60*1000)));
  var tarDay2=dateFormat(new Date(tarDay.getTime()-(1*24*60*60*1000)));
  var tarDay3=dateFormat(new Date(tarDay.getTime()-(2*24*60*60*1000)));
  var tarDay4=dateFormat(new Date(tarDay.getTime()-(3*24*60*60*1000)));
  var tarDay5=dateFormat(new Date(tarDay.getTime()-(4*24*60*60*1000)));
  var tarDay6=dateFormat(new Date(tarDay.getTime()-(5*24*60*60*1000)));
  var tarDay7=dateFormat(new Date(tarDay.getTime()-(6*24*60*60*1000)));
  return targetDay = tarDay1 + ","+ tarDay2 + ","+ tarDay3 + ","+ tarDay4 + ","+ tarDay5 + ","+ tarDay6 + ","+ tarDay7 
}