. 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();

对于真正的mysql样式输出使用下面的函数:2019/02/28 15:33:12

如果你点击下面的“运行代码片段”按钮 它将向您展示一个简单的实时数字时钟示例 演示程序将出现在代码片段的下面。

function getDateTime() { var now = new Date(); var year = now.getFullYear(); var month = now.getMonth()+1; var day = now.getDate(); var hour = now.getHours(); var minute = now.getMinutes(); var second = now.getSeconds(); if(month.toString().length == 1) { month = '0'+month; } if(day.toString().length == 1) { day = '0'+day; } if(hour.toString().length == 1) { hour = '0'+hour; } if(minute.toString().length == 1) { minute = '0'+minute; } if(second.toString().length == 1) { second = '0'+second; } var dateTime = year+'/'+month+'/'+day+' '+hour+':'+minute+':'+second; return dateTime; } // example usage: realtime clock setInterval(function(){ currentTime = getDateTime(); document.getElementById("digital-clock").innerHTML = currentTime; }, 1000); <div id="digital-clock"></div>

这个问题很古老，答案也很古老。现在我们可以使用moment.js来获取当前日期，而不是那些怪异的函数，这实际上非常简单。所有要做的就是在我们的项目中包括moment.js，并获得一个格式良好的日期，例如，通过:

moment().format("dddd, MMMM Do YYYY, h:mm:ss a");

我认为这使得在javascript中处理日期更容易。

我需要在后期特效里弄清楚这一点。以下是我从几个不同的来源获取元素后得出的结论——格式是MM/DD/YYYY HH:MM AM/PM

D = new Date(Date(00));
M = D.getMonth()+1;
H = D.getHours();
Mi = D.getMinutes();

N = "AM"
if (H >= 12)
N = "PM"
if (H > 12)
{
H = H-12
}

amtOfZeroes = 2;
isNeg = false;

if (M < 0)
{
M = Math.abs(M);
isNeg = true;
}
Mo = Math.round(M) + "";
while(Mo.length < amtOfZeroes)
{

Mo = "0" + Mo; 
}
if (isNeg)
Mo = "-" + Mo;

if (H < 0)
{
H = Math.abs(H);
isNeg = true;
}
Ho = Math.round(H) + "";
while(Ho.length < amtOfZeroes)
{
Ho = "0" + Ho; 
}
if (isNeg)
Ho = "-" + Ho;

if (Mi < 0)
{
Mi = Math.abs(Mi);
isNeg = true;
}
Min = Math.round(Mi) + "";
while(Min.length < amtOfZeroes)
{
Min = "0" + Min; 
}
if (isNeg)
Min = "-" + Min;

T = Ho + ":" + (Min)

Mo + "/" + D.getDate() + "/" + D.getFullYear() + "  " + T + " " + N

function UniqueDateTime(format='',language='en-US'){
    //returns a meaningful unique number based on current time, and milliseconds, making it virtually unique
    //e.g : 20170428-115833-547
    //allows personal formatting like more usual :YYYYMMDDHHmmSS, or YYYYMMDD_HH:mm:SS
    var dt = new Date();
    var modele="YYYYMMDD-HHmmSS-mss";
    if (format!==''){
      modele=format;
    }
    modele=modele.replace("YYYY",dt.getFullYear());
    modele=modele.replace("MM",(dt.getMonth()+1).toLocaleString(language, {minimumIntegerDigits: 2, useGrouping:false}));
    modele=modele.replace("DD",dt.getDate().toLocaleString(language, {minimumIntegerDigits: 2, useGrouping:false}));
    modele=modele.replace("HH",dt.getHours().toLocaleString(language, {minimumIntegerDigits: 2, useGrouping:false}));
    modele=modele.replace("mm",dt.getMinutes().toLocaleString(language, {minimumIntegerDigits: 2, useGrouping:false}));
    modele=modele.replace("SS",dt.getSeconds().toLocaleString(language, {minimumIntegerDigits: 2, useGrouping:false}));
    modele=modele.replace("mss",dt.getMilliseconds().toLocaleString(language, {minimumIntegerDigits: 3, useGrouping:false}));
    return modele;
}

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>