微信小程序获取今天，昨天，后天

onLoad: function(options) {  var that = this;  //获取明天  that.getDateStr(null,1)//只需要改变这里就OK，-1是昨天，0是今天，1是后一天}, getDateStr: function(today, addDayCount) {var date;if(today) {  date = new Date(today);}else{  date = new Date();}date.setDate(date.getDate() + addDayCount);//获取AddDayCount天后的日期   var y = date.getFullYear();  var m = date.getMonth() + 1;//获取当前月份的日期   var d = date.getDate();  if(m < 10){    m = '0' + m;  };  if(d < 10) {    d = '0' + d;  };  console.log( y + "-" + m + "-" + d)  return y + "-" + m + "-" + d;},