你如何在JavaScript中以12小时制(AM/PM)显示日期和时间?
en-US 的短 RegExp:
var d = new Date();
d = d.toLocaleTimeString().replace(/:\d+ /, ' '); // current time, e.g. "1:54 PM"
1:54 PM CDT
。要删除 CDT
,请将您的正则表达式更改为 .replace(/:\d+ |\CDT/g, ' ')
。虽然,CDT只是我的时区。如果您有不同的时区,我想您需要更改为该时区代码。 - sadmicrowavevar d = new Date();
var amOrPm = (d.getHours() < 12) ? "AM" : "PM";
var hour = (d.getHours() < 12) ? d.getHours() : d.getHours() - 12;
return d.getDate() + ' / ' + d.getMonth() + ' / ' + d.getFullYear() + ' ' + hour + ':' + d.getMinutes() + ' ' + amOrPm;
09:56 AM
如果小时数小于10,则在小时数前添加一个零
这里使用了ES6语法
const getTimeAMPMFormat = (date) => {
let hours = date.getHours();
let minutes = date.getMinutes();
const ampm = hours >= 12 ? 'PM' : 'AM';
hours = hours % 12;
hours = hours ? hours : 12; // the hour '0' should be '12'
hours = hours < 10 ? '0' + hours : hours;
// appending zero in the start if hours less than 10
minutes = minutes < 10 ? '0' + minutes : minutes;
return hours + ':' + minutes + ' ' + ampm;
};
console.log(getTimeAMPMFormat(new Date)); // 09:59 AM
希望本答案对新手更易读懂(尤其是与其他答案相比)。
这里是我在一些网站上实现的解决方案,用于通知该网站代码上次修改时间。它通过date.toLocaleDateString
的options
参数实现了AM/PM时间(参见相关Mozilla文档 在此)。
// Last time page code was updated/changed
const options = {
year: "numeric",
month: "long",
weekday: "long",
day: "numeric",
hour: "numeric",
minute: "numeric",
second: "numeric",
hour12: true // This is the line of code we care about here
/*
false: displays 24hs format for time
true: displays 12, AM and PM format
*/
};
let last = document.lastModified;
let date = new Date(last);
let local = date.toLocaleDateString("en-US", options);
let fullDate = `${local}`;
document.getElementById("updated").textContent = fullDate;
Saturday, May 28, 2022, 8:38:50 PM
<p>Last update: <span id="updated">_update_date_goes_here</span></p>
注意:在这种情况下,document.lastModified
存在一些奇怪的行为,具体取决于它是在本地运行还是在外部服务器上运行(参见此 Stack Overflow 问题)。尽管当我在我的 GitHub 页面上运行它时它能正确工作(您应该在页脚上看到它的效果)。
我发现它在这里运行良好。
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);
和 plunker 示例 在这里
<script>
var todayDate = new Date();
var getTodayDate = todayDate.getDate();
var getTodayMonth = todayDate.getMonth()+1;
var getTodayFullYear = todayDate.getFullYear();
var getCurrentHours = todayDate.getHours();
var getCurrentMinutes = todayDate.getMinutes();
var getCurrentAmPm = getCurrentHours >= 12 ? 'PM' : 'AM';
getCurrentHours = getCurrentHours % 12;
getCurrentHours = getCurrentHours ? getCurrentHours : 12;
getCurrentMinutes = getCurrentMinutes < 10 ? '0'+getCurrentMinutes : getCurrentMinutes;
var getCurrentDateTime = getTodayDate + '-' + getTodayMonth + '-' + getTodayFullYear + ' ' + getCurrentHours + ':' + getCurrentMinutes + ' ' + getCurrentAmPm;
alert(getCurrentDateTime);
</script>
var myTime = "15:30"
的时间字符串,
那么您可以使用以下代码获取上午或下午。var hour = parseInt(myTime.split(":")[0]) % 12;
var timeInAmPm = (hour == 0 ? "12": hour ) + ":" + myTime.split(":")[1] + " " + (parseInt(parseInt(myTime.split(":")[0]) / 12) < 1 ? "am" : "pm");
这里还有一种简单而且非常有效的方法:
var d = new Date();
var weekday = new Array(7);
weekday[0] = "Sunday";
weekday[1] = "Monday";
weekday[2] = "Tuesday";
weekday[3] = "Wednesday";
weekday[4] = "Thursday";
weekday[5] = "Friday";
weekday[6] = "Saturday";
var month = new Array(11);
month[0] = "January";
month[1] = "February";
month[2] = "March";
month[3] = "April";
month[4] = "May";
month[5] = "June";
month[6] = "July";
month[7] = "August";
month[8] = "September";
month[9] = "October";
month[10] = "November";
month[11] = "December";
var t = d.toLocaleTimeString().replace(/:\d+ /, ' ');
document.write(weekday[d.getDay()] + ',' + " " + month[d.getMonth()] + " " + d.getDate() + ',' + " " + d.getFullYear() + '<br>' + d.toLocaleTimeString());
</script></div><!-- #time -->
function startTime() {
const today = new Date();
let h = today.getHours();
let m = today.getMinutes();
let s = today.getSeconds();
var meridian = h >= 12 ? "PM" : "AM";
h = h % 12;
h = h ? h : 12;
m = m < 10 ? "0" + m : m;
s = s < 10 ? "0" + s : s;
var strTime = h + ":" + m + ":" + s + " " + meridian;
document.getElementById('time').innerText = strTime;
setTimeout(startTime, 1000);
}
startTime();
<h1 id='time'></h1>
警告:toLocaleTimeString() 的行为可能因地区/位置而异。
量好再切。 - Abandoned Cart