如何以12小时格式(AM/PM)显示JavaScript datetime对象?
当前回答
希望这个答案比其他答案更容易理解(尤其是对新手来说)。
以下是我在一些站点中实现的解决方案,用于通知上次修改站点代码的时间。它通过date的选项参数实现AM/PM时间。toLocaleDateString(参见相关的Mozilla文档)。
// 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 = `${local}`;
document.getElementById("updated").textContent = fullDate;
输出的格式是:
Saturday, May 28, 2022, 8:38:50 PM
该输出然后显示在以下HTML代码中:
<p>Last update: <span id="updated">_update_date_goes_here</span></p>
注意:在这个用例中,是文档。lastModified有一些奇怪的行为,这取决于它是在本地运行还是在外部服务器上运行(参见这个堆栈溢出问题)。虽然当我在我的GitHub页面上运行它时,它可以正常工作(你应该在网站的页脚处看到它在运行)。
其他回答
我的建议是使用moment js进行日期和时间操作。
https://momentjs.com/docs/#/displaying/format/
console.log(时刻)。格式(“hh: mm ')); < script src = " / / cdnjs.cloudflare.com/ajax/libs/moment.js/2.17.1/moment.min.js " > < /脚本>
在现代浏览器中,使用Intl。DateTimeFormat和强制12小时格式选项:
let now = new Date();
new Intl.DateTimeFormat('default',
{
hour12: true,
hour: 'numeric',
minute: 'numeric'
}).format(now);
// 6:30 AM
如果您添加更多选项,使用default将尊重浏览器的默认区域,但仍将输出12小时格式。
更新以获得更多压缩
const formatAMPM = (date) => {
let hours = date.getHours();
let minutes = date.getMinutes();
const ampm = hours >= 12 ? 'pm' : 'am';
hours %= 12;
hours = hours || 12;
minutes = minutes < 10 ? `0${minutes}` : minutes;
const strTime = `${hours}:${minutes} ${ampm}`;
return strTime;
};
console.log(formatAMPM(new Date()));
这里有另一种简单有效的方法:
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 -->
如果你不需要打印上午/下午,我发现以下内容很好很简洁:
var now = new Date();
var hours = now.getHours() % 12 || 12; // 12h instead of 24h, with 12 instead of 0.
这是基于@bbrame的回答。