I'm trying to use Javascript for formatting the time to a localized format using Intl.DateTimeFormat method.
I have several instances of time strings in 24h format i want to localize in a HTML page, for example:
<span class="timeclass">18:45</span> //and so on..
And i am able to format the time with the following code, which uses a Date object:
let locale = 'en-US'; // this variable changes, example 'en-UK', etc
let time = new Date('1971-12-12T18:45');
console.log(new Intl.DateTimeFormat(locale, {
hour: 'numeric',
minute: 'numeric',
}).format(time)); //output is "6:45 PM"
As the code shows, i added a dummy date in order for the Date object to be semantically correct. Now, i'm trying to write a function to replace all instances of times contained within timeelem classes:
var locale = 'en-US';
var timeformat = new Intl.DateTimeFormat(locale, {
hour: 'numeric',
minute: 'numeric',
});
timeelements = document.querySelectorAll('.timeclass');
timeelements.forEach((element) => {
timeelements.textContent= timeformat.format(timeelements.textContent);
});
But it is not working because it is getting the time in the format 18:45 instead of 1971-12-12T18:45. What is the best way to prepend such dummy date to the string? The date is only relevant for the localization function to work, by the way.
You can choose any date you want, as long as it is in the correct format. You can do something like this: WORKING DEMO
HTML
<span class="timeclass">18:45</span>
<span class="timeclass">18:15</span>
<span class="timeclass">11:45</span>
<span class="timeclass">02:45</span>
<span class="timeclass">22:45</span>
<span class="timeclass">23:45</span>
<span class="timeclass">18:00</span>
JAVASCRIPT
timeelements = document.querySelectorAll('.timeclass');
timeelements.forEach((element) => {
console.log("elem ", element.innerHTML);
// Append any date. Use your birthday.
const timeString12hr = new Date('1970-01-01T' + element.innerHTML + 'Z')
.toLocaleTimeString({}, {
timeZone: 'UTC',
hour12: true,
hour: 'numeric',
minute: 'numeric'
});
element.innerHTML = timeString12hr
});
------------------------UPDATED------------------------
var locale = "en-US";
var timeformat = new Intl.DateTimeFormat(locale, {
hour: 'numeric',
minute: 'numeric',
});
timeelements = document.querySelectorAll('.timeclass');
timeelements.forEach((element) => {
console.log("elem ", element.innerHTML);
const timeString12hr = new Date('1970-01-01T' + element.innerHTML + 'Z');
element.innerHTML = timeformat.format(timeString12hr)
});
Convert an input type time, to a timestamp for firestore
<input type="time" class="form-control job-field" id="starttime" name="starttimeadd" placeholder="Job Start Time" required>
This is what I have tried but no luck, I did have a couple of results trying a different method but that showed an invalid date or NaN.
var starttimestamp = moment.utc(moment("#starttimeadd")).format();
This is the expected result
This is my code
function addJob(){
var starttimeadd = $('#starttimeadd').val();
const starttimestamp = moment.utc(moment(starttimeadd)).format();
db.collection("jobs").doc().set({
starttime: starttimestamp,
})
.then(function() {
console.log("Document successfully written!");
})
.catch(function(error) {
console.error("Error writing document: ", error);
});
}
moment takes a date as a parameter, not an element ID like you're trying to do here. How about:
const startTimeAdd = document.getElementById("starttimeadd").value;
const starttimestamp = moment.utc(startTimeAdd).format();
Also worth considering that you may not need to use Moment for this - the official docs recommend reading an article on why you may not need Moment
Close enough. Using Intl.DateTimeFormat (no momentjs)
//code assumes that you have validated the input
var startTime = "01:00"; // document.querySelector("#starttime").value;
var formattedStartDateFromTime = getFormattedDateFromTime(startTime);
console.log(formattedStartDateFromTime);
function getFormattedDateFromTime(time) {
var timeParts = time.split(":");
var startDate = new Date();
startDate.setHours(+timeParts[0]);
startDate.setMinutes(+timeParts[1]);
startDate.setSeconds(0);
var options = {
year: 'numeric',
month: 'long',
day: 'numeric',
hour: 'numeric',
minute: 'numeric',
second: 'numeric',
timeZoneName: 'short'
};
return new Intl.DateTimeFormat('en', options).format(startDate);
}
Browser compatibility: Chrome, Edge, Firefox, IE11+
I'm using Intl library in my javascript code, as below:
const dateFormat = new Intl.DateTimeFormat(locale, {
day: '2-digit',
month: '2-digit',
year: 'numeric',
});
kk = new Date('1992-10-28')
dateFormat.format(kk, 'en-Us') ==> "10/28/1992"
But I want something like "dd/mm/yyyy" as response:
let format = dateFormat.getFormat('en-Us'); // --> "dd/mm/yyyy"
The Intl object doesn't allow you to specify the entire format, only parts of it. If you want a particular sequence of values, you can try a language value that fits or do it by hand. Almost any variant of English other than US will give d, m, y but the separator is another issue. Fortunately, "/" seems to be the default.
Surprisingly, if you provide an English variant that is not recognised, it will likely default to the peculiar US m/d/y sequence.
var d = new Date();
var options = {day:'2-digit', month:'2-digit', year:'numeric'}
console.log(d.toLocaleString('en-gb', options));
Otherwise, a library can help, but if you only want to support one format, a 2 or 3 line function will do.
function formatDMY(date) {
var z = function(n){return (n<10?'0':'')+n}
return z(date.getDate()) + '/' +
z(date.getMonth()+1) + '/' +
date.getFullYear();
}
console.log(formatDMY(new Date()));
I want the server to always serve dates in UTC in the HTML, and have JavaScript on the client site convert it to the user's local timezone.
Bonus if I can output in the user's locale date format.
Seems the most foolproof way to start with a UTC date is to create a new Date object and use the setUTC… methods to set it to the date/time you want.
Then the various toLocale…String methods will provide localized output.
Example:
// This would come from the server.
// Also, this whole block could probably be made into an mktime function.
// All very bare here for quick grasping.
d = new Date();
d.setUTCFullYear(2004);
d.setUTCMonth(1);
d.setUTCDate(29);
d.setUTCHours(2);
d.setUTCMinutes(45);
d.setUTCSeconds(26);
console.log(d); // -> Sat Feb 28 2004 23:45:26 GMT-0300 (BRT)
console.log(d.toLocaleString()); // -> Sat Feb 28 23:45:26 2004
console.log(d.toLocaleDateString()); // -> 02/28/2004
console.log(d.toLocaleTimeString()); // -> 23:45:26
Some references:
toLocaleString
toLocaleDateString
toLocaleTimeString
getTimezoneOffset
You can do it with moment.js (deprecated in 2021)
It's best to parse your date string from UTC as follows (create an ISO-8601 compatible string on the server to get consistent results across all browsers):
var m = moment("2013-02-08T09:30:26Z");
Now just use m in your application, moment.js defaults to the local timezone for display operations. There are many ways to format the date and time values or extract portions of it.
You can even format a moment object in the users locale like this:
m.format('LLL') // Returns "February 8 2013 8:30 AM" on en-us
To transform a moment.js object into a different timezone (i.e. neither the local one nor UTC), you'll need the moment.js timezone extension. That page has also some examples, it's pretty simple to use.
Note: Moment JS recommends more modern alternatives, so it is probably not a good choice for new projects.
You can use new Date().getTimezoneOffset()/60 for the timezone. There is also a toLocaleString() method for displaying a date using the user's locale.
Here's the whole list: Working with Dates
In JS there are no simple and cross platform ways to format local date time, outside of converting each property as mentioned above.
Here is a quick hack I use to get the local YYYY-MM-DD. Note that this is a hack, as the final date will not have the correct timezone anymore (so you have to ignore timezone). If I need anything else more, I use moment.js.
var d = new Date();
d = new Date(d.getTime() - d.getTimezoneOffset() * 60000)
var yyyymmdd = t.toISOString().slice(0, 10);
// 2017-05-09T08:24:26.581Z (but this is not UTC)
The d.getTimezoneOffset() returns the time zone offset in minutes, and the d.getTime() is in ms, hence the x 60,000.
2021 - you can use the browser native Intl.DateTimeFormat
const utcDate = new Date(Date.UTC(2020, 11, 20, 3, 23, 16, 738));
console.log(new Intl.DateTimeFormat().format(utcDate));
// expected output: "21/04/2021", my locale is Switzerland
Below is straight from the documentation:
const date = new Date(Date.UTC(2020, 11, 20, 3, 23, 16, 738));
// Results below assume UTC timezone - your results may vary
// Specify default date formatting for language (locale)
console.log(new Intl.DateTimeFormat('en-US').format(date));
// expected output: "12/20/2020"
// Specify default date formatting for language with a fallback language (in this case Indonesian)
console.log(new Intl.DateTimeFormat(['ban', 'id']).format(date));
// expected output: "20/12/2020"
// Specify date and time format using "style" options (i.e. full, long, medium, short)
console.log(new Intl.DateTimeFormat('en-GB', { dateStyle: 'full', timeStyle: 'long' }).format(date));
// Expected output "Sunday, 20 December 2020 at 14:23:16 GMT+11"
Once you have your date object constructed, here's a snippet for the conversion:
The function takes a UTC formatted Date object and format string.
You will need a Date.strftime prototype.
function UTCToLocalTimeString(d, format) {
if (timeOffsetInHours == null) {
timeOffsetInHours = (new Date().getTimezoneOffset()/60) * (-1);
}
d.setHours(d.getHours() + timeOffsetInHours);
return d.strftime(format);
}
// new Date(year, monthIndex [, day [, hours [, minutes [, seconds [, milliseconds]]]]])
var serverDate = new Date(2018, 5, 30, 19, 13, 15); // just any date that comes from server
var serverDateStr = serverDate.toLocaleString("en-US", {
year: 'numeric',
month: 'numeric',
day: 'numeric',
hour: 'numeric',
minute: 'numeric',
second: 'numeric'
})
var userDate = new Date(serverDateStr + " UTC");
var locale = window.navigator.userLanguage || window.navigator.language;
var clientDateStr = userDate.toLocaleString(locale, {
year: 'numeric',
month: 'numeric',
day: 'numeric'
});
var clientDateTimeStr = userDate.toLocaleString(locale, {
year: 'numeric',
month: 'numeric',
day: 'numeric',
hour: 'numeric',
minute: 'numeric',
second: 'numeric'
});
console.log("Server UTC date: " + serverDateStr);
console.log("User's local date: " + clientDateStr);
console.log("User's local date&time: " + clientDateTimeStr);
Here's what I've used in past projects:
var myDate = new Date();
var tzo = (myDate.getTimezoneOffset()/60)*(-1);
//get server date value here, the parseInvariant is from MS Ajax, you would need to do something similar on your own
myDate = new Date.parseInvariant('<%=DataCurrentDate%>', 'yyyyMMdd hh:mm:ss');
myDate.setHours(myDate.getHours() + tzo);
//here you would have to get a handle to your span / div to set. again, I'm using MS Ajax's $get
var dateSpn = $get('dataDate');
dateSpn.innerHTML = myDate.localeFormat('F');
The .getTimezoneOffset() method reports the time-zone offset in minutes, counting "westwards" from the GMT/UTC timezone, resulting in an offset value that is negative to what one is commonly accustomed to. (Example, New York time would be reported to be +240 minutes or +4 hours)
To the get a normal time-zone offset in hours, you need to use:
var timeOffsetInHours = -(new Date()).getTimezoneOffset()/60
Important detail:
Note that daylight savings time is factored into the result - so what this method gives you is really the time offset - not the actual geographic time-zone offset.
With date from PHP code I used something like this..
function getLocalDate(php_date) {
var dt = new Date(php_date);
var minutes = dt.getTimezoneOffset();
dt = new Date(dt.getTime() + minutes*60000);
return dt;
}
We can call it like this
var localdateObj = getLocalDate('2015-09-25T02:57:46');
I mix the answers so far and add to it, because I had to read all of them and investigate additionally for a while to display a date time string from db in a user's local timezone format.
The datetime string comes from a python/django db in the format: 2016-12-05T15:12:24.215Z
Reliable detection of the browser language in JavaScript doesn't seem to work in all browsers (see JavaScript for detecting browser language preference), so I get the browser language from the server.
Python/Django: send request browser language as context parameter:
language = request.META.get('HTTP_ACCEPT_LANGUAGE')
return render(request, 'cssexy/index.html', { "language": language })
HTML: write it in a hidden input:
<input type="hidden" id="browserlanguage" value={{ language }}/>
JavaScript: get value of hidden input e.g. en-GB,en-US;q=0.8,en;q=0.6/ and then take the first language in the list only via replace and regular expression
const browserlanguage = document.getElementById("browserlanguage").value;
var defaultlang = browserlanguage.replace(/(\w{2}\-\w{2}),.*/, "$1");
JavaScript: convert to datetime and format it:
var options = { hour: "2-digit", minute: "2-digit" };
var dt = (new Date(str)).toLocaleDateString(defaultlang, options);
See: https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/Date/toLocaleDateString
The result is (browser language is en-gb): 05/12/2016, 14:58
The best solution I've come across is to create [time display="llll" datetime="UTC TIME" /] Tags, and use javascript (jquery) to parse and display it relative to the user's time.
http://momentjs.com/ Moment.js
will display the time nicely.
You could use the following, which reports the timezone offset from GMT in minutes:
new Date().getTimezoneOffset();
Note :
- this function return a negative number.
getTimeZoneOffset() and toLocaleString are good for basic date work, but if you need real timezone support, look at mde's TimeZone.js.
There's a few more options discussed in the answer to this question
To convert date to local date use toLocaleDateString() method.
var date = (new Date(str)).toLocaleDateString(defaultlang, options);
To convert time to local time use toLocaleTimeString() method.
var time = (new Date(str)).toLocaleTimeString(defaultlang, options);
A very old question but perhaps this helps someone stumbling into this.
Below code formats an ISO8601 date string in a human-friendly format corresponding the user's time-zone and locale. Adapt as needed. For example: for your app, are the hours, minutes, seconds even significant to display to the user for dates more than 1 days, 1 week, 1 month, 1 year or whatever old?
Also depending on your application's implementation, don't forget to re-render periodically.
(In my code below at least every 24hours).
export const humanFriendlyDateStr = (iso8601) => {
// Examples (using Node.js):
// Get an ISO8601 date string using Date()
// > new Date()
// 2022-04-08T22:05:18.595Z
// If it was earlier today, just show the time:
// > humanFriendlyDateStr('2022-04-08T22:05:18.595Z')
// '3:05 PM'
// If it was during the past week, add the day:
// > humanFriendlyDateStr('2022-04-07T22:05:18.595Z')
// 'Thu 3:05 PM'
// If it was more than a week ago, add the date
// > humanFriendlyDateStr('2022-03-07T22:05:18.595Z')
// '3/7, 2:05 PM'
// If it was more than a year ago add the year
// > humanFriendlyDateStr('2021-03-07T22:05:18.595Z')
// '3/7/2021, 2:05 PM'
// If it's sometime in the future return the full date+time:
// > humanFriendlyDateStr('2023-03-07T22:05:18.595Z')
// '3/7/2023, 2:05 PM'
const datetime = new Date(Date.parse(iso8601))
const now = new Date()
const ageInDays = (now - datetime) / 86400000
let str
// more than 1 year old?
if (ageInDays > 365) {
str = datetime.toLocaleDateString([], {
year: 'numeric',
month: 'numeric',
day: 'numeric',
hour: 'numeric',
minute: 'numeric',
})
// more than 1 week old?
} else if (ageInDays > 7) {
str = datetime.toLocaleDateString([], {
month: 'numeric',
day: 'numeric',
hour: 'numeric',
minute: 'numeric',
})
// more than 1 day old?
} else if (ageInDays > 1) {
str = datetime.toLocaleDateString([], {
weekday: 'short',
hour: 'numeric',
minute: 'numeric',
})
// some time today?
} else if (ageInDays > 0) {
str = datetime.toLocaleTimeString([], {
timeStyle: 'short',
})
// in the future?
} else {
str = datetime.toLocaleDateString([], {
year: 'numeric',
month: 'numeric',
day: 'numeric',
hour: 'numeric',
minute: 'numeric',
})
}
return str
}
Inspired from: https://alexwlchan.net/2020/05/human-friendly-dates-in-javascript/
Tested using Node.js
Don't know how to do locale, but javascript is a client side technology.
usersLocalTime = new Date();
will have the client's time and date in it (as reported by their browser, and by extension the computer they are sitting at). It should be trivial to include the server's time in the response and do some simple math to guess-timate offset.