如何使用javascript获取上个月和下个月的html结果

var currentDate = new Date();
var currentMonth = currentDate.getMonth();
currentDate.setMonth(currentMonth - 1);
var previousMonth = currentDate.getMonth() + 1;
var previousYear = currentDate.getFullYear();

var htmlResult = '<div>上个月是：' + previousYear + '年' + previousMonth + '月</div>';
console.log(htmlResult);

var currentDate = new Date();
var currentMonth = currentDate.getMonth();
currentDate.setMonth(currentMonth + 1);
var nextMonth = currentDate.getMonth() + 1;
var nextYear = currentDate.getFullYear();

var htmlResult = '<div>下个月是：' + nextYear + '年' + nextMonth + '月</div>';
console.log(htmlResult);