// get current time for UTC timezone
const d = new Date();
const year = d.getUTCFullYear();
const month = d.getUTCMonth();
const day = d.getUTCDate();
// set time to begin day UTC
const startTime = Date.UTC(year, month, day, 0, 0, 0, 0);
//set time to end day UTC
const endTime = Date.UTC(year, month, day, 23, 59, 0, 0);

var start = new Date(); start.setUTCHours (0, 0, 0, 0); var end = new Date(); end.setUTCHours(23日,59,59999); alert(start.toUTCString() + ':' + end.toUTCString());

如果需要从中获取UTC时间，可以使用UTC()。

供参考(合并后的Tvanfosson)

当你调用函数时，它将返回实际日期=>日期

export const today = {
  iso: {
    start: () => new Date(new Date().setHours(0, 0, 0, 0)).toISOString(),
    now: () => new Date().toISOString(),
    end: () => new Date(new Date().setHours(23, 59, 59, 999)).toISOString()
  },
  local: {
  start: () => new Date(new Date(new Date().setHours(0, 0, 0, 0)).toString().split('GMT')[0] + ' UTC').toISOString(),
  now: () => new Date(new Date().toString().split('GMT')[0] + ' UTC').toISOString(),
  end: () => new Date(new Date(new Date().setHours(23, 59, 59, 999)).toString().split('GMT')[0] + ' UTC').toISOString()
  }
}

//如何使用

today.local.now(); //"2018-09-07T01:48:48.000Z" BAKU +04:00
today.iso.now(); // "2018-09-06T21:49:00.304Z" * 

*适用于即时时间类型的Java8自动转换您的本地时间取决于您的地区。(如果你打算写全局应用程序)

使用dayjs库，使用startOf和endOf方法，如下所示:

当地格林尼治时间:

const start = dayjs().startOf('day'); // set to 12:00 am today
const end = dayjs().endOf('day'); // set to 23:59 pm today

UTC的:

const utc = require('dayjs/plugin/utc');
dayjs.extend(utc);

const start = dayjs.utc().startOf('day'); 
const end = dayjs.utc().endOf('day'); 

使用(已弃用的)momentjs库，这可以通过startOf()和endOf()方法在时刻的当前日期对象上实现，将字符串'day'作为参数传递:

当地格林尼治时间:

var start = moment().startOf('day'); // set to 12:00 am today
var end = moment().endOf('day'); // set to 23:59 pm today

UTC的:

var start = moment.utc().startOf('day'); 
var end = moment.utc().endOf('day'); 

// get current time for UTC timezone
const d = new Date();
const year = d.getUTCFullYear();
const month = d.getUTCMonth();
const day = d.getUTCDate();
// set time to begin day UTC
const startTime = Date.UTC(year, month, day, 0, 0, 0, 0);
//set time to end day UTC
const endTime = Date.UTC(year, month, day, 23, 59, 0, 0);

我们可以用矩。

// for day start time
moment(moment().startOf('day')).format('HH:mm')

// for day end time
moment(moment().endOf('day')).format('HH:mm')