Develop Reference

Solving a time and day issue

I don't understand how this works. can someone explain it to me? Especially the variable name "prepand" which I've seen as "prepend" when I look it up. Also, what does the ? mean in (hour>12)?
var today = new Date();
var day = today.getDay();
var daylist = ["Sunday","Monday","Tuesday","Wednesday
","Thursday","Friday","Saturday"];
console.log("Today is : " + daylist[day] + ".");
var hour = today.getHours();
var minute = today.getMinutes();
var second = today.getSeconds();
var prepand = (hour >= 12)? " PM ":" AM ";
hour = (hour >= 12)? hour - 12: hour;
if (hour===0 && prepand===' PM ')
{
if (minute===0 && second===0)
{
hour=12;
prepand=' Noon';
}
else
{
hour=12;
prepand=' PM';
}
}
if (hour===0 && prepand===' AM ')
{
if (minute===0 && second===0)
{
hour=12;
prepand=' Midnight';
}
else
{
hour=12;
prepand=' AM';
}
}
console.log("Current Time : "+hour + prepand + " : " + minute + " : " + second);

var prepand = (hour >= 12)? " PM ":" AM ";
This translates to:
var prepand;
if (hour >= 12){
prepand = "PM";
} else {
prepand = "AM";
}
This writing is a shorthand expression called ternary. It is used to assign conditional values to variables in this case.

That is a basic code which gets the current date and tell you the day and time by manipulating the date. Check the comments corresponding to the lines.
Prepand variable is used to add the AM/PM with the time
Read here in details about Date
var today = new Date(); //Creates a JavaScript Date instance that represents a single moment in time
var day = today.getDay(); // return the index of the day
var daylist = ["Sunday", "Monday", "Tuesday", "Wednesday ","Thursday","Friday ","Saturday "];
console.log("Today is : " + daylist[day] + ".");
var hour = today.getHours();// getHours() method returns the hour for the specified date
var minute = today.getMinutes();//getMinutes() method returns the minutes in the specified date
var second = today.getSeconds();
var prepand = (hour >= 12) ? " PM " : " AM ";
hour = (hour >= 12) ? hour - 12 : hour; //? is a part of ternary operator which will check if hour >=12 or not. If >= then prepand in PM otherwise AM
if (hour === 0 && prepand === ' PM ') {
if (minute === 0 && second === 0) {
hour = 12;
prepand = ' Noon';
} else {
hour = 12;
prepand = ' PM';
}
}
if (hour === 0 && prepand === ' AM ') {
if (minute === 0 && second === 0) {
hour = 12;
prepand = ' Midnight';
} else {
hour = 12;
prepand = ' AM';
}
}
console.log("Current Time : " + hour + prepand + " : " + minute + " : " +
second);

Jquery function to Increment one hours based on time input string

I have string value in this format.
9:00 am
i want it to be like this.
9:00 am - 10:00 am
second hour must be 1 greater then first one. for example if time is
7:00 am then it should be 7:00 am - 8:00 am
how can i do that using jquery?
i tried this but its not working as it works now.
var time= "9:00 am"
var nexttime=time.setHours(time.getHours()+1)
alert(nexttime);
getting error of
time.getHours is not a function

You can try this :
function increaseTimeByOne(timeStr) {
var splitedTimeStr = timeStr.split(':');
var hours = parseInt(splitedTimeStr[0]);
var meridiem = splitedTimeStr[1].split(" ")[1];
var minutes = splitedTimeStr[1].split(" ")[0];
var nextHours = (hours + 1);
var nextMeridiem;
if (hours >= 11) {
if (meridiem.toLowerCase() == "am") {
nextMeridiem = "pm";
} else if (meridiem.toLowerCase() == "pm") {
nextMeridiem = "am";
}
if (nextHours > 12) {
nextHours = nextHours - 12;
}
} else {
nextMeridiem = meridiem;
}
return nextHours + ":" + minutes + " " + nextMeridiem;
}
and using above function as
var timestr="9:00 am";
var next_hour = increaseTimeByOne(timeStr);
alert(next_hour);

refer this
var time=new Date();
time.setHours(9, 00, 00);
var nexttime=(time.getHours()+1);
alert(nexttime);
// to get hrs mins and seconds
var nexttime=(time.getHours()+1) +":"+time.getMinutes()+":"+time.getSeconds();

YOu can make your time string like:
function increaseTimeByOne(t) {
var s = t.split(':');
var n = parseInt(s[0], 10);
var nt = (n + 1) + ":00 ";
var ampm = n >= 11 ? "pm" : "am";
return t + " - " + nt + ampm;
}
console.log(increaseTimeByOne('9:00 am'));
console.log(increaseTimeByOne('11:00 am'));
console.log(increaseTimeByOne('12:00 pm'));

How to check if current time falls within a specific range considering also minutes

I am doing a Website for Restaurants Home Delivery ,depending on Restaurant's Home Delivery Timings i need to enable / disable Order Now Button
I have got startTime and End Time in 12 Hour format .
This is the code
var startTime = '8:30 AM' ;
var endTime = '6:30 PM' ;
var formatTime = (function () {
function addZero(num) {
return (num >= 0 && num < 10) ? "0" + num : num + "";
}
return function (dt) {
var formatted = '';
if (dt) {
var hours24 = dt.getHours();
var hours = ((hours24 + 11) % 12) + 1;
formatted = [formatted, [addZero(hours), addZero(dt.getMinutes())].join(":"),hours24>11?"pm" :"am"].join(" ");
}
return formatted;
}
})();
var currentTime = formatTime(new Date());
I need to check if the current time is in between startTime and EndTime or not
If its only Hours ,i could have extracted the first character before colon from startTime ,endTime and currentTime and done a comparision like this
if(currentTime >= startTime && currentTime <= endTime)
{
alert('Restaurant Open');
}
else
{
alert('Restaurant Closed');
}
But i need to take the minutes also in consideration ,so could you please let me how to do this comparsion if minutes were takein in consideration ??
How to check if current time falls within a specific range considering also minutes

Something like this should work
var startTime = '6:30 PM';
var endTime = '8:30 AM';
var now = new Date();
var startDate = dateObj(startTime); // get date objects
var endDate = dateObj(endTime);
if (startDate > endDate) { // check if start comes before end
var temp = startDate; // if so, assume it's across midnight
startDate = endDate; // and swap the dates
endDate = temp;
}
var open = now < endDate && now > startDate ? 'open' : 'closed'; // compare
console.log('Restaurant is ' + open);
function dateObj(d) { // date parser ...
var parts = d.split(/:|\s/),
date = new Date();
if (parts.pop().toLowerCase() == 'pm') parts[0] = (+parts[0]) + 12;
date.setHours(+parts.shift());
date.setMinutes(+parts.shift());
return date;
}
.as-console-wrapper {top : 0!important}
It splits those times and adds 12 to PM times, then creates date objects that can easily be compared.

Doesn't seem to work with times passing midnight, try changing the time from 6:30PM to 2:30AM. A good solution is to use momentjs with the moment-range plugin
function inTimeRange(time, startTime, endTime)
{
//Setup today vars
var today = new moment(new Date());
var ayear = today.year();
var amonth = today.month() + 1; // 0 to 11
var adate = today.date();
amonth = String(amonth).length < 2 ? "0" + amonth : amonth;
adate = String(adate).length < 2 ? "0" + adate : adate;
//Create moment objects
var moment1, moment2;
var temp = endTime.split(" ");
if(temp[1].toLowerCase() == "am")
{
var test1 = ayear + "-" + amonth + "-" + adate + " " + startTime;
var test2 = ayear + "-" + amonth + "-" + adate + " " + endTime;
//Make sure that both times aren't morning times
if(moment(test2).isAfter(test1))
{
var moment1String = ayear + "-" + amonth + "-" + adate + " " + startTime;
var moment2String = ayear + "-" + amonth + "-" + adate + " " + endTime;
}
else
{
var moment1String = ayear + "-" + amonth + "-" + adate + " " + startTime;
var moment2String = ayear + "-" + amonth + "-" + (adate + 1) + " " + endTime;
}
moment1 = moment(moment1String, "YYYY-MM-DD HH:mm A");
moment2 = moment(moment2String, "YYYY-MM-DD HH:mm A");
}
else
{
var moment1String = ayear + "-" + amonth + "-" + adate + " " + startTime;
var moment2String = ayear + "-" + amonth + "-" + adate + " " + endTime;
moment1 = moment(moment1String, "YYYY-MM-DD HH:mm A");
moment2 = moment(moment2String, "YYYY-MM-DD HH:mm A");
}
//Run check
var start = moment1.toDate();
var end = moment2.toDate();
var when;
if(String(time).toLowerCase() == "now")
{
when = moment(new Date());
}
else
{
var timeMoment1String = ayear + "-" + amonth + "-" + adate + " " + time;
when = moment(timeMoment1String);
}
var range = moment().range(start, end);
return when.within(range);
}

var startTime = '02:30 AM';
var endTime = '13:00 PM';
var now = new Date();
var startDate = dateObj(startTime);
var endDate = dateObj(endTime);
alert(endDate)
var open = now < endDate && now > startDate ? 'open' : 'closed';
alert('Restaurant is ' + open);
function dateObj(d) {
var parts = d.split(/:|\s/),
date = new Date();
if (parts.pop().toLowerCase() == 'pm') parts[0] = (+parts[0]) + 12;
date.setHours(+parts.shift());
date.setMinutes(+parts.shift());
return date;
}
var startTime = '8:30 AM';
var endTime = '6:30 PM';
var now = new Date();
var startDate = dateObj(startTime);
var endDate = dateObj(endTime);
var open = now < endDate && now > startDate ? 'open' : 'closed';
alert('Restaurant is ' + open);
function dateObj(d) {
var parts = d.split(/:|\s/),
date = new Date();
if (parts.pop().toLowerCase() == 'pm') parts[0] = (+parts[0]) + 12;
date.setHours(+parts.shift());
date.setMinutes(+parts.shift());
return date;
}

I have done something similar to this. My app was receiving times in military time. So in the case where times didn't pass into the next day (i.e. start time of 09:00 and end time of 17:00 you would just check if you are between those times.
In the case of the end time being after midnight (i.e. start time of 15:00 and end time of 01:00) then there are three cases:
You are in a time after both start and end times, like 16:00, in which case you are inside business hours
You are in a time before both start and end times, like 00:30, in which case you are also inside business hours.
You are in a time after the end time, but before the start time, like 02:30, in which case you are outside of business hours
Here is my code sample:
const isCurrentDayPart = (dayPart) => {
let currentTime = moment();
let startTime = moment(dayPart.startTime, "HH:mm");
let endTime = moment(dayPart.endTime, "HH:mm");
if (dayPart.startTime < dayPart.endTime) {
return currentTime.isBetween(startTime, endTime);
} else {
if (currentTime.isAfter(endTime) && currentTime.isAfter(startTime)) {
return true;
} else if (currentTime.isBefore(endTime) && currentTime.isBefore(startTime)) {
return true;
}
}
return false;
};

convert 12-hour hh:mm AM/PM to 24-hour hh:mm

Is there any simple way to convert 12-hour hh:mm AM/PM to 24-hour hh:mm using jquery?
Note: not using any other libraries.
I have a var time = $("#starttime").val() that returns a hh:mm AM/PM.

Try this
var time = $("#starttime").val();
var hours = Number(time.match(/^(\d+)/)[1]);
var minutes = Number(time.match(/:(\d+)/)[1]);
var AMPM = time.match(/\s(.*)$/)[1];
if(AMPM == "PM" && hours<12) hours = hours+12;
if(AMPM == "AM" && hours==12) hours = hours-12;
var sHours = hours.toString();
var sMinutes = minutes.toString();
if(hours<10) sHours = "0" + sHours;
if(minutes<10) sMinutes = "0" + sMinutes;
alert(sHours + ":" + sMinutes);

This question needs a newer answer :)
const convertTime12to24 = (time12h) => {
const [time, modifier] = time12h.split(' ');
let [hours, minutes] = time.split(':');
if (hours === '12') {
hours = '00';
}
if (modifier === 'PM') {
hours = parseInt(hours, 10) + 12;
}
return `${hours}:${minutes}`;
}
console.log(convertTime12to24('01:02 PM'));
console.log(convertTime12to24('05:06 PM'));
console.log(convertTime12to24('12:00 PM'));
console.log(convertTime12to24('12:00 AM'));

This will help :
function getTwentyFourHourTime(amPmString) {
var d = new Date("1/1/2013 " + amPmString);
return d.getHours() + ':' + d.getMinutes();
}
Example :
getTwentyFourHourTime("8:45 PM"); // "20:45"
getTwentyFourHourTime("8:45 AM"); // "8:45"
Update :
Note : There should be a space for timestring between "Time" and "am/pm".

I had to do something similar but I was generating a Date object so I ended up making a function like this:
function convertTo24Hour(time) {
var hours = parseInt(time.substr(0, 2));
if(time.indexOf('am') != -1 && hours == 12) {
time = time.replace('12', '0');
}
if(time.indexOf('pm') != -1 && hours < 12) {
time = time.replace(hours, (hours + 12));
}
return time.replace(/(am|pm)/, '');
}
I think this reads a little easier. You feed a string in the format h:mm am/pm.
var time = convertTo24Hour($("#starttime").val().toLowerCase());
var date = new Date($("#startday").val() + ' ' + time);
Examples:
$("#startday").val('7/10/2013');
$("#starttime").val('12:00am');
new Date($("#startday").val() + ' ' + convertTo24Hour($("#starttime").val().toLowerCase()));
Wed Jul 10 2013 00:00:00 GMT-0700 (PDT)
$("#starttime").val('12:00pm');
new Date($("#startday").val() + ' ' + convertTo24Hour($("#starttime").val().toLowerCase()));
Wed Jul 10 2013 12:00:00 GMT-0700 (PDT)
$("#starttime").val('1:00am');
new Date($("#startday").val() + ' ' + convertTo24Hour($("#starttime").val().toLowerCase()));
Wed Jul 10 2013 01:00:00 GMT-0700 (PDT)
$("#starttime").val('12:12am');
new Date($("#startday").val() + ' ' + convertTo24Hour($("#starttime").val().toLowerCase()));
Wed Jul 10 2013 00:12:00 GMT-0700 (PDT)
$("#starttime").val('3:12am');
new Date($("#startday").val() + ' ' + convertTo24Hour($("#starttime").val().toLowerCase()));
Wed Jul 10 2013 03:12:00 GMT-0700 (PDT)
$("#starttime").val('9:12pm');
new Date($("#startday").val() + ' ' + convertTo24Hour($("#starttime").val().toLowerCase()));
Wed Jul 10 2013 21:12:00 GMT-0700 (PDT)

Here my solution including seconds:
function convert_to_24h(time_str) {
// Convert a string like 10:05:23 PM to 24h format, returns like [22,5,23]
var time = time_str.match(/(\d+):(\d+):(\d+) (\w)/);
var hours = Number(time[1]);
var minutes = Number(time[2]);
var seconds = Number(time[3]);
var meridian = time[4].toLowerCase();
if (meridian == 'p' && hours < 12) {
hours += 12;
}
else if (meridian == 'a' && hours == 12) {
hours -= 12;
}
return [hours, minutes, seconds];
};

function timeConversion(s) {
var time = s.toLowerCase().split(':');
var hours = parseInt(time[0]);
var _ampm = time[2];
if (_ampm.indexOf('am') != -1 && hours == 12) {
time[0] = '00';
}
if (_ampm.indexOf('pm') != -1 && hours < 12) {
time[0] = hours + 12;
}
return time.join(':').replace(/(am|pm)/, '');
}
Call the function with string params:
timeConversion('17:05:45AM')
or
timeConversion('07:05:45PM')

i must recommend a library: Moment
code:
var target12 = '2016-12-08 9:32:45 PM';
console.log(moment(target12, 'YYYY-MM-DD h:m:s A').format('YYYY-MM-DD HH:mm:ss'));

For anybody reading this in the future, here is a simpler answer:
var s = "11:41:02PM";
var time = s.match(/\d{2}/g);
if (time[0] === "12") time[0] = "00";
if (s.indexOf("PM") > -1) time[0] = parseInt(time[0])+12;
return time.join(":");

Single line code for calc time 12 hours to 24 hours
Any format of the input working fine
const convertTime12to24 = (time12h) => moment(time12h, 'hh:mm A').format('HH:mm');
console.log(convertTime12to24('06:30 pm'));
console.log(convertTime12to24('06:00 am'));
console.log(convertTime12to24('9:00 am'));
console.log(convertTime12to24('9pm'));
<script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.29.1/moment.min.js"></script>

In case you're looking for a solution that converts ANY FORMAT to 24 hours HH:MM correctly.
function get24hTime(str) {
str = String(str).toLowerCase().replace(/\s/g, '');
var has_am = str.indexOf('am') >= 0;
var has_pm = str.indexOf('pm') >= 0;
// first strip off the am/pm, leave it either hour or hour:minute
str = str.replace('am', '').replace('pm', '');
// if hour, convert to hour:00
if (str.indexOf(':') < 0) str = str + ':00';
// now it's hour:minute
// we add am/pm back if striped out before
if (has_am) str += ' am';
if (has_pm) str += ' pm';
// now its either hour:minute, or hour:minute am/pm
// put it in a date object, it will convert to 24 hours format for us
var d = new Date("1/1/2011 " + str);
// make hours and minutes double digits
var doubleDigits = function(n) {
return (parseInt(n) < 10) ? "0" + n : String(n);
};
return doubleDigits(d.getHours()) + ':' + doubleDigits(d.getMinutes());
}
console.log(get24hTime('6')); // 06:00
console.log(get24hTime('6am')); // 06:00
console.log(get24hTime('6pm')); // 18:00
console.log(get24hTime('6:11pm')); // 18:11
console.log(get24hTime('6:11')); // 06:11
console.log(get24hTime('18')); // 18:00
console.log(get24hTime('18:11')); // 18:11

I needed this function for a project. I tried devnull69's but I was having some trouble, mostly because the string input is very specific for the am/pm section and I would've needed to change my validation. I messed around with Adrian P.'s jsfiddle and ended up with a version that seems to work better for a larger variety of date formats. Here is the fiddle: http://jsfiddle.net/u91q8kmt/2/.
Here is the function:
function ConvertTimeformat(format, str) {
var hours = Number(str.match(/^(\d+)/)[1]);
var minutes = Number(str.match(/:(\d+)/)[1]);
var AMPM = str.match(/\s?([AaPp][Mm]?)$/)[1];
var pm = ['P', 'p', 'PM', 'pM', 'pm', 'Pm'];
var am = ['A', 'a', 'AM', 'aM', 'am', 'Am'];
if (pm.indexOf(AMPM) >= 0 && hours < 12) hours = hours + 12;
if (am.indexOf(AMPM) >= 0 && hours == 12) hours = hours - 12;
var sHours = hours.toString();
var sMinutes = minutes.toString();
if (hours < 10) sHours = "0" + sHours;
if (minutes < 10) sMinutes = "0" + sMinutes;
if (format == '0000') {
return (sHours + sMinutes);
} else if (format == '00:00') {
return (sHours + ":" + sMinutes);
} else {
return false;
}
}

With this you can have the following:
Sample Input: 07:05:45PM
Sample Output: 19:05:45
function timeConversion(s) {
let output = '';
const timeSeparator = ':'
const timeTokenType = s.substr(s.length - 2 , 2).toLowerCase();
const timeArr = s.split(timeSeparator).map((timeToken) => {
const isTimeTokenType =
timeToken.toLowerCase().indexOf('am') > 0 ||
timeToken.toLowerCase().indexOf('pm');
if(isTimeTokenType){
return timeToken.substr(0, 2);
} else {
return timeToken;
}
});
const hour = timeArr[0];
const minutes = timeArr[1];
const seconds = timeArr[2];
const hourIn24 = (timeTokenType === 'am') ? parseInt(hour) - 12 :
parseInt(hour) + 12;
return hourIn24.toString()+ timeSeparator + minutes + timeSeparator + seconds;
}
Hope you like it !

Because all the answers so far seem to be verbose, here's a simple minimalist solution:
/* Convert h:mm a/p to H:mm
* i.e. 12 hour time to 24 hour time
* #param {string} time - h:mm a/p format
* #returns {string} time in H:mm format
*/
function to24HrTime(time) {
let [hr, min, ap] = time.toLowerCase().match(/\d+|[a-z]+/g) || [];
return `${(hr % 12) + (ap == 'am'? 0 : 12)}:${min}`;
}
['9:02 am',
'9:02 pm',
'9:02am',
'9:02pm',
'12:15 AM',
'12:01 PM',
].forEach(time => console.log(`${time} -> ${to24HrTime(time)}`));
That assumes the input string has a suitable format and values. A more robust version is:
/* Given 12 hr time, return24 hr time
* #param {string} time - time in format h:mm am/pm
* h must be in range 1 to 12
* mm must be in range 00 to 59
* am/pm is not case sensitive
* #returns {string} time in 24 hr format H:mm
* H in range 0 to 23
* mm in range 00 to 59
*
*/
function to24HrTime(time = new Date().toLocaleString('en',{hour:'numeric', minute:'2-digit', hour12:true})) {
let [hr, min, ap] = String(time).toLowerCase().match(/\d+|[a-z]+/g) || [];
// If time is valid, return reformatted time
// Otherwise return undefined
return /^([1-9]|1[0-2]):[0-5]\d\s?(am|pm)/i.test(time)? `${(hr%12)+(ap=='am'?0:12)}:${min}` : void 0;
}
// Examples
// Without arguments
console.log(`No args -> ${to24HrTime()}`);
// Valid input
['9:02 am',
'9:02 pm',
'9:02am',
'9:02pm',
'12:15 AM',
'12:01 PM',
// Invalid input
'12', // Missing mins & ap
'99:05 am', // hrs out of range
'0:05 am', // hrs out of range
'9:60 am', // mins out of range
'9:09 pp', // ap out of range
{}, // Random object
].forEach(time => console.log(`${time} -> ${to24HrTime(time)}`));

An extended version of #krzysztof answer with the ability to work on time that has space or not between time and modifier.
const convertTime12to24 = (time12h) => {
const [fullMatch, time, modifier] = time12h.match(/(\d?\d:\d\d)\s*(\w{2})/i);
let [hours, minutes] = time.split(':');
if (hours === '12') {
hours = '00';
}
if (modifier === 'PM') {
hours = parseInt(hours, 10) + 12;
}
return `${hours}:${minutes}`;
}
console.log(convertTime12to24('01:02 PM'));
console.log(convertTime12to24('05:06 PM'));
console.log(convertTime12to24('12:00 PM'));
console.log(convertTime12to24('12:00 AM'));

based on meeting CodeSkill #1
validation of format should be another function :)
function convertTimeFrom12To24(timeStr) {
var colon = timeStr.indexOf(':');
var hours = timeStr.substr(0, colon),
minutes = timeStr.substr(colon+1, 2),
meridian = timeStr.substr(colon+4, 2).toUpperCase();
var hoursInt = parseInt(hours, 10),
offset = meridian == 'PM' ? 12 : 0;
if (hoursInt === 12) {
hoursInt = offset;
} else {
hoursInt += offset;
}
return hoursInt + ":" + minutes;
}
console.log(convertTimeFrom12To24("12:00 AM"));
console.log(convertTimeFrom12To24("12:00 PM"));
console.log(convertTimeFrom12To24("11:00 AM"));
console.log(convertTimeFrom12To24("01:00 AM"));
console.log(convertTimeFrom12To24("01:00 PM"));

Converting AM/PM Time string to 24 Hours Format.
Example 9:30 PM to 21:30
function get24HrsFrmAMPM(timeStr) {
if (timeStr && timeStr.indexOf(' ') !== -1 && timeStr.indexOf(':') !== -1) {
var hrs = 0;
var tempAry = timeStr.split(' ');
var hrsMinAry = tempAry[0].split(':');
hrs = parseInt(hrsMinAry[0], 10);
if ((tempAry[1] == 'AM' || tempAry[1] == 'am') && hrs == 12) {
hrs = 0;
} else if ((tempAry[1] == 'PM' || tempAry[1] == 'pm') && hrs != 12) {
hrs += 12;
}
return ('0' + hrs).slice(-2) + ':' + ('0' + parseInt(hrsMinAry[1], 10)).slice(-2);
} else {
return null;
}
}

//here is my solution.
function timeConversion(s) {
// Write your code here
let amPM = s.indexOf('AM') !== -1 ? 'AM' : 'PM';
let tString = s.toString().replace(/AM|PM/gi,'');
let splitTime = tString.split(':');
let h = splitTime[0];
let m = splitTime[1];
let sec = splitTime[2];
let twntyfr = amPM === 'PM' && parseInt(h) !== 12 ? parseInt(h)+12 : h;
if(parseInt(twntyfr) === 12 && amPM === 'AM') twntyfr = '00';
return twntyfr+':'+m+':'+sec;
}

HackerRank TimeConversion Solution
12-hour AM/PM format, to military (24-hour) time
function timeConversion(s) {
let time = 0
let hour = s.slice(0, 2)
let toD = s.slice(-2)
if (toD === 'AM' && hour == 12) {
time = `00${s.slice(2, s.length -2)}`
} else {
if (toD === 'PM' && hour < 12) {
time = `${Number(12 + parseInt(hour))}${s.slice(2, s.length - 2)}`
} else {
time = s.slice(0, s.length - 2)
}
}
return console.log(time)
}
timeConversion('12:00:17AM') // 00:00:17
timeConversion('09:21:33PM') // 21:21:33
timeConversion('12:43:53PM') // 12:43:53

function getDisplayDatetime() {
var d = new Date("February 04, 2011 19:00"),
hh = d.getHours(), mm = d.getMinutes(), dd = "AM", h = hh;
mm=(mm.toString().length == 1)? mm = "0" + mm:mm;
h=(h>=12)?hh-12:h;
dd=(hh>=12)?"PM":"AM";
h=(h == 0)?12:h;
var textvalue=document.getElementById("txt");
textvalue.value=h + ":" + mm + " " + dd;
}
</script>
</head>
<body>
<input type="button" value="click" onclick="getDisplayDatetime()">
<input type="text" id="txt"/>

dateFormat.masks.armyTime= 'HH:MM';
now.format("armyTime");

function convertTo24Hour(time) {
time = time.toUpperCase();
var hours = parseInt(time.substr(0, 2));
if(time.indexOf('AM') != -1 && hours == 12) {
time = time.replace('12', '0');
}
if(time.indexOf('PM') != -1 && hours < 12) {
time = time.replace(hours, (hours + 12));
}
return time.replace(/(AM|PM)/, '');
}

date --date="2:00:01 PM" +%T
14:00:01
date --date="2:00 PM" +%T | cut -d':' -f1-2
14:00
var="2:00:02 PM"
date --date="$var" +%T
14:00:02

You could try this more generic function:
function from12to24(hours, minutes, meridian) {
let h = parseInt(hours, 10);
const m = parseInt(minutes, 10);
if (meridian.toUpperCase() === 'PM') {
h = (h !== 12) ? h + 12 : h;
} else {
h = (h === 12) ? 0 : h;
}
return new Date((new Date()).setHours(h,m,0,0));
}
Note it uses some ES6 functionality.

I've created a bit of an adaptation of script #devnull69 submitted. I felt for my application it would be more useful as a function that returned the value that I could, then use as a variable.
HTML
<input type="text" id="time_field" />
<button>Submit</submit>
jQuery
$(document).ready(function() {
function convertTime(time) {
var hours = Number(time.match(/^(\d\d?)/)[1]);
var minutes = Number(time.match(/:(\d\d?)/)[1]);
var AMPM = time.match(/\s(AM|PM)$/i)[1];
if((AMPM == 'PM' || AMPM == 'pm') && hours < 12) {
hours = hours + 12;
}
else if((AMPM == 'AM' || AMPM == "am") && hours == 12) {
hours = hours - 12;
}
var sHours = hours.toString();
var sMinutes = minutes.toString();
if(hours < 10) {
sHours = "0" + sHours;
}
else if(minutes < 10) {
sMinutes = "0" + sMinutes;
}
return sHours + ":" + sMinutes;
}
$('button').click(function() {
alert(convertTime($('#time_field').val()));
});
});

single and easy js function for calc time meridian in real time
JS
function convertTime24to12(time24h) {
var timex = time24h.split(':');
if(timex[0] !== undefined && timex [1] !== undefined)
{
var hor = parseInt(timex[0]) > 12 ? (parseInt(timex[0])-12) : timex[0] ;
var minu = timex[1];
var merid = parseInt(timex[0]) < 12 ? 'AM' : 'PM';
var res = hor+':'+minu+' '+merid;
document.getElementById('timeMeridian').innerHTML=res.toString();
}
}
Html
<label for="end-time">Hour <i id="timeMeridian"></i> </label>
<input type="time" name="hora" placeholder="Hora" id="end-time" class="form-control" onkeyup="convertTime24to12(this.value)">

Typescript solution based off of #krzysztof-dąbrowski 's answer
export interface HoursMinutes {
hours: number;
minutes: number;
}
export function convert12to24(time12h: string): HoursMinutes {
const [time, modifier] = time12h.split(' ');
let [hours, minutes] = time.split(':');
if (hours === '12') {
hours = '00';
}
if (minutes.length === 1) {
minutes = `0${minutes}`;
}
if (modifier.toUpperCase() === 'PM') {
hours = parseInt(hours, 10) + 12 + '';
}
return {
hours: parseInt(hours, 10),
minutes: parseInt(minutes, 10)
};
}

Tested for all the use cases
function timeConversion(s) {
let h24;
let m24;
let sec24;
const splittedDate = s.split(":");
const h = parseInt(splittedDate[0], 10);
const m = parseInt(splittedDate[1], 10);
const sec = parseInt(splittedDate[2][0] + splittedDate[2][1], 10);
const meridiem = splittedDate[2][2] + splittedDate[2][3];
if (meridiem === "AM") {
if (h === 12) {
h24 = '00';
} else {
h24 = h;
if (h24 < 10) {
h24 = '0' + h24;
}
}
m24 = m;
sec24 = sec;
} else if (meridiem === "PM") {
if (h === 12) {
h24 = h
} else {
h24 = h + 12;
if (h24 < 10) {
h24 = '0' + h24;
}
}
m24 = m;
sec24 = sec;
}
if (m24 < 10) {
m24 = '0' + m24;
}
if (sec24 < 10) {
sec24 = '0' + sec24;
}
return h24 + ":" + m24 + ":" + sec24;
}
Here is the jsfiddle working example

Short ES6 code
const convertFrom12To24Format = (time12) => {
const [sHours, minutes, period] = time12.match(/([0-9]{1,2}):([0-9]{2}) (AM|PM)/).slice(1);
const PM = period === 'PM';
const hours = (+sHours % 12) + (PM ? 12 : 0);
return `${('0' + hours).slice(-2)}:${minutes}`;
}
const convertFrom24To12Format = (time24) => {
const [sHours, minutes] = time24.match(/([0-9]{1,2}):([0-9]{2})/).slice(1);
const period = +sHours < 12 ? 'AM' : 'PM';
const hours = +sHours % 12 || 12;
return `${hours}:${minutes} ${period}`;
}

I just solved this issue on HackerRank, so I'm here to share my result
function timeConversion(s) {
const isPM = s.indexOf('PM') !== -1;
let [hours, minutes, seconds] = s.replace(isPM ? 'PM':'AM', '').split(':');
if (isPM) {
hours = parseInt(hours, 10) + 12;
hours = hours === 24 ? 12 : hours;
} else {
hours = parseInt(hours, 10);
hours = hours === 12 ? 0 : hours;
if (String(hours).length === 1) hours = '0' + hours;
}
const time = [hours, minutes, seconds].join(':');
return time;
}
This works for inputs like 06:40:03AM.

function formatto24(date) {
let ampm = date.split(" ")[1];
let time = date.split(" ")[0];
if (ampm == "PM") {
let hours = time.split(":")[0];
let minutes = time.split(":")[1];
let seconds = time.split(":")[2];
let hours24 = JSON.parse(hours) + 12;
return hours24 + ":" + minutes + ":" + seconds;
} else {
return time;
}
}

javascript, jquery time format

I have a question, how can I change time from 24hr format to 12, the easiest way, in javascript or Jquery .
This is what I have :
TempDate = $.datepicker.formatDate('MM dd, yy', TempDate);
var ChangeDate = TempDate + " " + TradeTime;
now TradeTime= 15:59 , but I wanna be 3:59PM
What is the easiest way , or can I use datapicker or to force this format in the same time with date.
Thanks

I'm afraid you will just have to do it manually, quick n dirty, for now ;)
function to12Hrs(strHrs, strMin) {
var hrs = Number(strHrs);
var min = Number(strMin);
var ampm = "am";
if(isNaN(hrs) || isNaN(min) || hrs > 23 || hrs < 0) {
throw ("Invalid Date " + str24Hrs);
}
if(hrs >= 12) {
hrs = (hrs - 12) || 12;
ampm = "pm";
}
var strHr = (hrs < 10) ? "0".concat(hrs) : hrs;
var strMin = (min < 10) ? "0".concat(min) : min;
return (strHr + ":" + strMin + ampm);
}
var arr = "12:30".split(":");
alert(to12Hrs(arr[0], arr[1])); // 12:30pm
arr = "11:00".split(":");
alert(to12Hrs(arr[0], arr[1])); // 11:00am
arr = "02:00".split(":");
alert(to12Hrs(arr[0], arr[1])); // 02:00am
arr = "20:00".split(":");
alert(to12Hrs(arr[0], arr[1])); // 08:00pm

This helped me :
TradeTime = ("" + TradeTime).split(":",2);
if (TradeTime[0] < 12)
{
a_p = "AM";
}
else
{
a_p = "PM";
}
if (TradeTime[0] == 0)
{
TradeTime[0] = 12;
}
if (TradeTime[0] > 12)
{
TradeTime[0] = TradeTime[0] - 12;
}