如何以12小时格式(AM/PM)显示JavaScript datetime对象?
当前回答
函数formatAMPM(date) { var hours = date.getHours(); var minutes = date.getMinutes(); Var ampm =小时>= 12 ?'pm': 'am'; 小时=小时% 12; 小时=小时?时长:12小时;//小时'0'应该是'12' 分钟=分钟< 10 ?'0'+minutes: minutes; var strTime = hours + ':' + minutes + ' + ampm; 返回strTime; } console.log (formatAMPM(新日期));
其他回答
function getDateTime() {
var now = new Date();
var year = now.getFullYear();
var month = now.getMonth() + 1;
var day = now.getDate();
if (month.toString().length == 1) {
month = '0' + month;
}
if (day.toString().length == 1) {
day = '0' + day;
}
var hours = now.getHours();
var minutes = now.getMinutes();
var ampm = hours >= 12 ? 'pm' : 'am';
hours = hours % 12;
hours = hours ? hours : 12;
minutes = minutes < 10 ? '0' + minutes : minutes;
var timewithampm = hours + ':' + minutes + ' ' + ampm;
var dateTime = monthNames[parseInt(month) - 1] + ' ' + day + ' ' + year + ' ' + timewithampm;
return dateTime;
}
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
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 = `${local}`;
document.getElementById("updated").textContent = fullDate;
输出的格式是:
Saturday, May 28, 2022, 8:38:50 PM
该输出然后显示在以下HTML代码中:
<p>Last update: <span id="updated">_update_date_goes_here</span></p>
注意:在这个用例中,是文档。lastModified有一些奇怪的行为,这取决于它是在本地运行还是在外部服务器上运行(参见这个堆栈溢出问题)。虽然当我在我的GitHub页面上运行它时,它可以正常工作(你应该在网站的页脚处看到它在运行)。
function formatTime( d = new Date(), ampm = true ) { var hour = d.getHours(); if ( ampm ) { var a = ( hour >= 12 ) ? 'PM' : 'AM'; hour = hour % 12; hour = hour ? hour : 12; // the hour '0' should be '12' } var hour = checkDigit(hour); var minute = checkDigit(d.getMinutes()); var second = checkDigit(d.getSeconds()); // https://stackoverflow.com/questions/1408289/how-can-i-do-string-interpolation-in-javascript return ( ampm ) ? `${hour}:${minute}:${second} ${a}` : `${hour}:${minute}:${second}`; } function checkDigit(t) { return ( t < 10 ) ? `0${t}` : t; } document.querySelector("#time1").innerHTML = formatTime(); document.querySelector("#time2").innerHTML = formatTime( new Date(), false ); <p>ampm true: <span id="time1"></span> (default)</p> <p>ampm false: <span id="time2"></span></p>
如果你把时间设置为字符串,输入var myTime = "15:30" 然后您可以使用下面的代码来获取am pm。
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");