我的建议是使用moment js进行日期和时间操作。

https://momentjs.com/docs/#/displaying/format/

console.log(时刻)。格式(“hh: mm ')); < script src = " / / cdnjs.cloudflare.com/ajax/libs/moment.js/2.17.1/moment.min.js " > < /脚本>

这是最简单的方法，你可以实现这使用三元操作符，或者你也可以使用if else代替!

const d = new Date();
let hrs = d.getHours();
let m = d.getMinutes();
// Condition to add zero before minute
let min = m < 10 ? `0${m}` : m;
const currTime = hrs >= 12 ? `${hrs - 12}:${min} pm` : `${hrs}:${min} am`;
console.log(currTime);

我发现它在这里工作得很好。

var date_format = '12'; /* FORMAT CAN BE 12 hour (12) OR 24 hour (24)*/
 
 
var d       = new Date();
var hour    = d.getHours();  /* Returns the hour (from 0-23) */
var minutes     = d.getMinutes();  /* Returns the minutes (from 0-59) */
var result  = hour;
var ext     = '';
 
if(date_format == '12'){
    if(hour > 12){
        ext = 'PM';
        hour = (hour - 12);
        result = hour;

        if(hour < 10){
            result = "0" + hour;
        }else if(hour == 12){
            hour = "00";
            ext = 'AM';
        }
    }
    else if(hour < 12){
        result = ((hour < 10) ? "0" + hour : hour);
        ext = 'AM';
    }else if(hour == 12){
        ext = 'PM';
    }
}
 
if(minutes < 10){
    minutes = "0" + minutes; 
}
 
result = result + ":" + minutes + ' ' + ext; 
 
console.log(result);

这是活塞的例子

en-US的短RegExp:

var d = new Date();
d = d.toLocaleTimeString().replace(/:\d+ /, ' '); // current time, e.g. "1:54 PM"

   const formatAMPM = (date) => {
    try {
      let time = date.split(" ");
      let hours = time[4].split(":")[0];
      let minutes = time[4].split(":")[1];
      hours = hours || 12;
      const ampm = hours >= 12 ? " PM" : " AM";
      minutes = minutes < 10 ? `${minutes}` : minutes;
      hours %= 12;
      const strTime = `${hours}:${minutes} ${ampm}`;
      return strTime;
    } catch (e) {
      return "";
    }
  };

const startTime = "2021-12-07T17:00:00.073Z"
formatAMPM(new Date(startTime).toUTCString())

或者只是简单地执行以下代码:

    <script>
        time = function() {
            var today = new Date();
            var h = today.getHours();
            var m = today.getMinutes();
            var s = today.getSeconds();
            m = checkTime(m);
            s = checkTime(s);
            document.getElementById('txt_clock').innerHTML = h + ":" + m + ":" + s;     
            var t = setTimeout(function(){time()}, 0);
        }

        time2 = function() {
            var today = new Date();
            var h = today.getHours();
            var m = today.getMinutes();
            var s = today.getSeconds();
            m = checkTime(m);
            s = checkTime(s);
            if (h>12) {
                document.getElementById('txt_clock_stan').innerHTML = h-12 + ":" + m + ":" + s;
            }               
            var t = setTimeout(function(){time2()}, 0);
        }

        time3 = function() {
            var today = new Date();
            var h = today.getHours();
            var m = today.getMinutes();
            var s = today.getSeconds();
            if (h>12) {
                document.getElementById('hour_line').style.width = h-12 + 'em'; 
            }
            document.getElementById('minute_line').style.width = m + 'em';  
            document.getElementById('second_line').style.width = s + 'em';  
            var t = setTimeout(function(){time3()}, 0);
        }

        checkTime = function(i) {
            if (i<10) {i = "0" + i};  // add zero in front of numbers < 10
            return i;
        }           
    </script>