看看这个也许会对你有用

<script language="JavaScript">
var dayarray=new Array("Sunday","Monday",
 "Tuesday","Wednesday","Thursday","Friday","Saturday")

var montharray=new Array("January","February","March",
 "April","May","June","July","August","September",
 "October","November","December")

function getthedate(){
var mydate=new Date()
var year=mydate.getYear()
if (year < 1000)
year+=1900
var day=mydate.getDay()
var month=mydate.getMonth()
var daym=mydate.getDate()
if (daym<10)
daym="0"+daym
var hours=mydate.getHours()
var minutes=mydate.getMinutes()
var seconds=mydate.getSeconds()
var dn="AM"
if (hours>=12)
dn="PM"
if (hours>12){
hours=hours-12
}
if (hours==0)
hours=12
if (minutes<=9)
minutes="0"+minutes
if (seconds<=9)
seconds="0"+seconds
//change font size here
var cdate="<small><font color='000000' face='Arial'><b>"+dayarray[day]+", 
    "+montharray[month]+" "+daym+", "+year+" "+hours+":"
 +minutes+":"+seconds+" "+dn
    +"</b></font></small>"
if (document.all)
document.all.clock.innerHTML=cdate
else if (document.getElementById)
document.getElementById("clock").innerHTML=cdate
else
document.write(cdate)
}
 if (!document.all&&!document.getElementById)
  getthedate()
  function goforit(){
  if (document.all||document.getElementById)
 setInterval("getthedate()",1000)
}

 </script>

enter code here

 <span id="clock"></span>

. getmonth()返回一个从零开始的数字，所以为了得到正确的月份，你需要加1，所以在五月调用. getmonth()将返回4而不是5。

因此，在代码中，我们可以使用currentdate.getMonth()+1来输出正确的值。此外:

.getDate()返回月份的日期<-这是你想要的 .getDay()是Date对象的一个单独方法，它将返回一个整数，表示一周中的当前日期(0-6)0 ==星期日等

所以你的代码应该是这样的:

var currentdate = new Date(); 
var datetime = "Last Sync: " + currentdate.getDate() + "/"
                + (currentdate.getMonth()+1)  + "/" 
                + currentdate.getFullYear() + " @ "  
                + currentdate.getHours() + ":"  
                + currentdate.getMinutes() + ":" 
                + currentdate.getSeconds();

JavaScript Date实例继承自Date.prototype。您可以修改构造函数的原型对象，以影响JavaScript Date实例继承的属性和方法

您可以使用Date原型对象创建一个新方法，该方法将返回今天的日期和时间。这些新方法或属性将由Date对象的所有实例继承，因此在需要重用此功能时特别有用。

// For todays date;
Date.prototype.today = function () { 
    return ((this.getDate() < 10)?"0":"") + this.getDate() +"/"+(((this.getMonth()+1) < 10)?"0":"") + (this.getMonth()+1) +"/"+ this.getFullYear();
}

// For the time now
Date.prototype.timeNow = function () {
     return ((this.getHours() < 10)?"0":"") + this.getHours() +":"+ ((this.getMinutes() < 10)?"0":"") + this.getMinutes() +":"+ ((this.getSeconds() < 10)?"0":"") + this.getSeconds();
}

然后，您可以通过执行以下操作简单地检索日期和时间:

var newDate = new Date();
var datetime = "LastSync: " + newDate.today() + " @ " + newDate.timeNow();

或者将该方法调用为内联，这样它就是-

var datetime = "LastSync: " + new Date().today() + " @ " + new Date().timeNow();

我善意的回答是使用这个小小的JS: https://github.com/rhroyston/clock-js

clock.now   --> 1462248501241
clock.time  --> 11:08 PM
clock.weekday   --> monday
clock.day   --> 2
clock.month --> may
clock.year  --> 2016
clock.since(1462245888784)  --> 44 minutes
clock.until(1462255888784)  --> 2 hours
clock.what.time(1462245888784)  --> 10:24 PM
clock.what.weekday(1461968554458)   --> friday
clock.what.day('14622458887 84')    --> 2
clock.what.month(1461968554458) --> april
clock.what.year('1461968554458')    --> 2016
clock.what.time()   --> 11:11 PM
clock.what.weekday('14619685abcd')  -->     clock.js error : expected unix timestamp as argument
clock.unit.seconds  --> 1000
clock.unit.minutes  --> 60000
clock.unit.hours    --> 3600000
clock.unit.days --> 86400000
clock.unit.weeks    --> 604800000
clock.unit.months   --> 2628002880
clock.unit.years    --> 31536000000

getDay()获取星期几。3号是星期三。你需要getDate()，它会返回18。

同样，getMonth()从0开始，你需要加1来得到4(四月)。

演示:http://jsfiddle.net/4zVxp/

只使用:

var d = new Date();
document.write(d.toLocaleString());
document.write("<br>");

试试这个:

var today = new Date();
var date = today.getFullYear()+'-'+(today.getMonth()+1)+'-'+today.getDate();
var time = today.getHours() + ":" + today.getMinutes() + ":" + today.getSeconds();
var dateTime = date+' '+time;

输出:

2022-3-3 15:52:45