从当前日期推算出7天前

var myDate = new Date(); //获取今天日期

myDate.setDate(myDate.getDate() - 7);

var dateArray = [];

var dateTemp;

var flag = 1;

for (var i = 0; i < 7; i++) {

    dateTemp = (myDate.getMonth()+1)+"-"+myDate.getDate();

    dateArray.push(dateTemp);

    myDate.setDate(myDate.getDate() + flag);

}