日期转化为2小时前，1分钟前等

记住获取时间的表达

let now = new Date().getTime()

function getDateDiff(dateTimeStamp){
 var now = new Date().getTime();
 var diffValue = now - dateTimeStamp;
 if(diffValue < 0){
  //若日期不符则弹出窗口告之
  //alert("结束日期不能小于开始日期！");
  }
 var monthC =diffValue/month;
 var weekC =diffValue/(7*day);
 var dayC =diffValue/day;
 var hourC =diffValue/hour;
 var minC =diffValue/minute;
 if(monthC>=1){
  result="发表于" + parseInt(monthC) + "个月前";
  }
  else if(weekC>=1){
  result="发表于" + parseInt(weekC) + "周前";
  }
  else if(dayC>=1){
  result="发表于"+ parseInt(dayC) +"天前";
  }
  else if(hourC>=1){
  result="发表于"+ parseInt(hourC) +"个小时前";
  }
  else if(minC>=1){
  result="发表于"+ parseInt(minC) +"分钟前";
  }else
  result="刚刚发表";
 return result;
}