下面是一个保留GMT时间和初始日期时间的答案

var date = new Date(); var first_date = new Date(date); //Make a copy of the date we want the first and last days from first_date.setUTCDate(1); //Set the day as the first of the month var last_date = new Date(first_date); //Make a copy of the calculated first day last_date.setUTCMonth(last_date.getUTCMonth() + 1); //Add a month last_date.setUTCDate(0); //Set the date to 0, this goes to the last day of the previous month console.log(first_date.toJSON().substring(0, 10), last_date.toJSON().substring(0, 10)); //Log the dates with the format yyyy-mm-dd

试试这个。

lastDateofTheMonth = new Date(year, month, 0)

例子:

new Date(2012, 8, 0)

输出:

Date {Fri Aug 31 2012 00:00:00 GMT+0900 (Tokyo Standard Time)}

试试这个:

function _getEndOfMonth(time_stamp) {
    let time = new Date(time_stamp * 1000);
    let month = time.getMonth() + 1;
    let year = time.getFullYear();
    let day = time.getDate();
    switch (month) {
        case 1:
        case 3:
        case 5:
        case 7:
        case 8:
        case 10:
        case 12:
            day = 31;
            break;
        case 4:
        case 6:
        case 9:
        case 11:
            day = 30;
            break;
        case 2:
            if (_leapyear(year))
                day = 29;
            else
                day = 28;
            break
    }
    let m = moment(`${year}-${month}-${day}`, 'YYYY-MM-DD')
    return m.unix() + constants.DAY - 1;
}

function _leapyear(year) {
    return (year % 100 === 0) ? (year % 400 === 0) : (year % 4 === 0);
}

你可以通过下面的代码获取当月的第一个和最后一个日期:

var dateNow = new Date();  
var firstDate = new Date(dateNow.getFullYear(), dateNow.getMonth(), 1);  
var lastDate = new Date(dateNow.getFullYear(), dateNow.getMonth() + 1, 0);

或者如果你想用自定义格式格式化日期，那么你可以使用moment js

var dateNow= new Date();  
var firstDate=moment(new Date(dateNow.getFullYear(),dateNow.getMonth(), 1)).format("DD-MM-YYYY");  
var currentDate = moment(new Date()).format("DD-MM-YYYY"); //to  get the current date var lastDate = moment(new
 Date(dateNow.getFullYear(), dateNow.getMonth() + 1, 0)).format("DD-MM-YYYY"); //month last date

对lebreeze提供的解决方案稍加修改:

function daysInMonth(iMonth, iYear)
{
    return new Date(iYear, iMonth, 0).getDate();
}

我的同事偶然发现了以下可能是一个更简单的解决方案

function daysInMonth(iMonth, iYear)
{
    return 32 - new Date(iYear, iMonth, 32).getDate();
}

窃取自http://snippets.dzone.com/posts/show/2099