I would like to have an input field with a button next to it.
On the input field I will enter a date like this:
2011-07-08
And when I hit the button it should read the time that has been entered on the input field and subtract it with 3 months and one day.
Is this possible?
Thanks in advance
Yes. First you read the date and you convert to a date object
var dateString = document.getElementById('id of your field').value,
date = new Date(dateString);
then you subtract 91 days and output the result
date.setDate(date.getDate() - 91);
alert(date.toString());
Here I assume for simplicity that you actually want 91 days and not 3 months and one day. If you want three months and one day you will do
date.setMonth(date.getMonth() - 3);
date.setDate(date.getDate() - 1);
alert(date.toString());
The Date object will take care of overflows, leap years and everything.
If you want to write it to same field, taking care of zeroes, you can do
function assureTwoDigits(number) {
if (number > 9) {
return '-' + number;
}
else {
return '-0' + number;
}
}
and change the last line to
document.getElementById('id of your field').value = date.getFullYear() + assureToDigits(date.getMonth()) + assureTwoDigits(date.getDate());
You can use Date objects (see here):
extract year, moth and day from the string (using a regular expression or splitting by '-')
buid a new Date object with that data
subtract the date interval
build the string back
The simplest way would be to split it into an array, then use a couple of if/else statements:
var date = (whatever you're pulling the date in as).split('-');
if (date[1] > 3)
date[1] = date[1] - 3;
else
date[0] = date[0] - 1;
var dateOverflow = date[1]-3;
date[1] = 12 - dateOverflow;
And then the same for the days.
Yes, it's possible and it's the most clean if you can do it without some arcane regex magic. Start by converting the date to a Date object:
// this will get you a date object from the string:
var myDate = new Date("2011-07-08");
// subtract 3 months and 1 day
myDate.setMonth(myDate.getMonth()-3);
myDate.setDay(myDate.getMonth(), myDate.getDay()-1);
// And now you have the day and it will be correct according to the number of days in a month etc
alert(myDate);
Related
I'd like to check the date if it's next month from the current.
Some test cases here
2020.1.1 2019.12.30 // true
2019.11.30 2019.10.10 // true
2019.12.11 2019.12.1 // false
So as you can see, I'd like to check if the date is next month from now.
Hope to get the brilliant idea!
Best
Kinji
You could try this approach, we have to handle the case when the dates are in the same year and also for December and January of the next year.
A simple algorithm can be created, whereby we multiply the year by 12, add the month and get the difference of this score between the two dates. As long as the value of this is 1 or -1 we have months that are adjacent. I'm presuming you only need to check if the first parameter is the next month to the second parameter, so we check for a difference of 1.
function isNextMonth(timeStamp1, timeStamp2, format = "YYYY.MM.DD") {
let dt1 = moment(timeStamp1, format);
let dt2 = moment(timeStamp2, format);
return ((dt1.year()*12 + dt1.month() - dt2.year()*12 - dt2.month()) === 1);
}
let inputs = [['2020.1.1','2019.12.30'],['2019.11.30', '2019.10.10'], ['2019.12.11','2019.12.1'], ['2020.12.1','2021.1.1'], ['2020.6.1','2020.5.1'], ['2021.1.1','2019.12.1'], ['2019.3.1', '2019.4.1']];
for(let [inputa, inputb] of inputs) {
console.log(`isNextMonth(${inputa}, ${inputb}): ${isNextMonth(inputa, inputb)}`);
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.24.0/moment.min.js"></script>
A very simple solution would be to use Moment’s isSame. This only checks the month. If you also want to make sure that the year matches you would have to make sure that nextMonth.getYear() matches dateToCheck.getYear()
var dateToCheck = new Date(2019, 11, 30)
var nextMonth = new Date()
nextMonth.setMonth(dateToCheck.getMonth() + 1)
moment(dateToCheck).isSame(nextMonth, 'month');
I have a date string like this 20/09/2018 12:00 AM. I need to stop to put the previous date than today. I have searched the web for it, but no answer found with this format.
I need the default date format of JavaScript so that I can compare with new Date() value. When I use the following format it show the message that says invalid date because of my dd/MM/yyyy hh:mm tt format.
alert(new Date("20/09/2018 12:00 AM"));
Igor recommended using moment.js to solve this — it is a widely used date/time library.
With moment.js you can do this:
var m = moment("20/09/2018 3:14 PM", "DD/MM/YYYY h:mm a");
var d = m.toDate();
The first line creates a "moment" object by parsing the date according to the format string specified as the second argument. See http://momentjs.com/docs/#/parsing/
The second line gets the native javascript Date object that the moment object encapsulates; however, moment can do so many things you may not need to get back that native object.
See the moment docs.
Your format isn't valid, thus you're getting invalid date error. So, using your format(dd/MM/yyyy hh:mm tt) we'll grab the year, month, day, hours and the minutes, then we'll reformat it as an acceptable format by the Date constructor and create a Date instance.
Here's a function that do all what being said and returns a Date instance which you can compare it with another Date instance:
function convertToDate(str) {
// replace '/' with '-'
str = str.replace(/\//ig, '-');
/**
* extracting the year, month, day, hours and minutes.
* the month, day and hours can be 1 or 2 digits(the leading zero is optional).
* i.e: '4/3/2022 2:18 AM' is the same as '04/03/2022 02:18 AM' => Notice the absence of the leading zero.
**/
var y = /\-([\d]{4})/.exec(str)[1],
m = /\-([\d]{2}|[\d])/.exec(str)[1],
d = /([\d]{2}|[\d])\-/.exec(str)[1],
H = /\s([\d]{2}|[\d]):/.exec(str)[1],
i = /:([\d]{2})/.exec(str)[1],
AMorPM = /(AM|PM)/.exec(str)[1];
// return a Date instance.
return new Date(y + '-' + m + '-' + d + ' ' + H + ':' + i + ' ' + AMorPM)
}
// testing...
var str1 = '20/09/2018 12:00 AM';
var str2 = '8/2/2018 9:00 PM'; // leading zero is omitted.
console.log(convertToDate(str1));
console.log(convertToDate(str2));
The Date depends on the user's/server's location, two users may have
different results.
Learn more
about Date.
Hope I pushed you further.
I'd like to use a Javascript within my zapier.com-zap. Here is what I am trying to do for five consecutive days now:
I have a date (whatever custom format you need), need to subtract two working days from it and output it to DD-MM-YYYY using Javascript. Sounds really simple, but I don't get it to work.
I hope someone out there can help me with this! Thank you very much.
I forgot to mention an essential thing, sorry. If the result is a Sunday or Saturday I need the date of the last working day (Friday).
If you're willing to use external libraries, MomentJS is a really popular tool for parsing and modifying JavaScript dates and would make this really simple:
Example 1: Subtract 2 Days and Format
var date = new Date(),
formatted = moment(date).subtract(2, 'days').format('DD-MM-YYYY');
document.getElementById('date').innerHTML = date;
document.getElementById('example').innerHTML = formatted;
<script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.11.2/moment.min.js"></script>
This example takes today's date (<span id="date"></span>), subtracts 2 days from it,
and then displays it below in the desired format (DD-MM-YYYY):
<p id="example"></p>
Example 2: Subtract 2 Working Days and Format
If by working days you mean Monday to Friday, all you'd need to do here is determine whether the day held in your date variable was a Monday or Tuesday, then adjust the value passed in to MomentJS's subtract method accordingly. We can do this using MomentJS's get day of week function:
var date = new Date(),
formatted, daysToSubtract;
switch (moment(date).day()) {
// Sunday = 3 days
case 0:
daysToSubtract = 3;
break;
// Monday and Tuesday = 4 days
case 1:
case 2:
daysToSubtract = 4;
break;
// Subtract 2 days otherwise.
default:
daysToSubtract = 2;
break;
}
formatted = moment(date).subtract(daysToSubtract, 'days').format('DD-MM-YYYY');
document.getElementById('date').innerHTML = date;
document.getElementById('example').innerHTML = formatted;
<script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.11.2/moment.min.js"></script>
This example takes today's date (<span id="date"></span>), subtracts 2 working days (Monday to Friday) from it,
and then displays it below in the desired format (DD-MM-YYYY):
<p id="example"></p>
While I agree with #James Donnelly that momentjs is awesome, here is how you can achieve your task without using an extra library. I created this helper function to do exactly what you're asking. Just pass in your date and however many days you want to add/subtract to it (-2 in your case).
function addDaysToDate(date, days)
{
var result = new Date(date);
result.setDate(result.getDate() + days);
var dd = result.getDate();
var mm = result.getMonth() + 1; // January starts at 0.
var yyyy = result.getFullYear();
if (dd < 10)
{
dd = '0' + dd
}
if (mm < 10)
{
mm = '0' + mm
}
return dd + '/' + mm + '/' + yyyy;
}
I am trying to prepopulate a date into an html "date" input field, but it ignores the values I try to pass:
<html>
...
<input id='date' type='date'>
...
</html>
<script>
...
var myDate = new Date();
$("#date").val(myDate);
...
I have also tried passing the date object as a string
var myDate = new Date().toDateString();
$("#date").val(myDate);
When I open the form, the date field is blank. If I eliminate the type="date" tag, the value shows up as a string, but then I don't have access to the datepicker. How do I pre-populate a date input and still have use of the datepicker? I'm stumped.
Thanks.
It must be set in ISO-format.
(function () {
var date = new Date().toISOString().substring(0, 10),
field = document.querySelector('#date');
field.value = date;
console.log(field.value);
})()
http://jsfiddle.net/GZ46K/
Why Not to Use toISOString()
The <input type='date'> field takes a value in ISO8601 format (reference), but you should not use the Date.prototype.toISOString() function for its value because, before outputting an ISO8601 string, it converts/represents the date/time to UTC standard time (read: changes the time zone) (reference). Unless you happen to be working in or want that time standard, you will introduce a bug where your date will sometimes, but not always, change.
Populate HTML5 Date Input from Date Object w/o Time Zone Change
The only reliable way to get a proper input value for <input type='date'> without messing with the time zone that I've seen is to manually use the date component getters. We pad each component according to the HTML date format specification (reference):
let d = new Date();
let datestring = d.getFullYear().toString().padStart(4, '0') + '-' + (d.getMonth()+1).toString().padStart(2, '0') + '-' + d.getDate().toString().padStart(2, '0');
document.getElementById('date').value = datestring;
/* Or if you want to use jQuery...
$('#date').val(datestring);
*/
<input id='date' type='date'>
Populate HTML5 Date & Time Fields from Date Object w/o Time Zone Change
This is beyond the scope of the original question, but for anyone wanting to populate both date & time HTML5 input fields from a Date object, here is what I came up with:
// Returns a 2-member array with date & time strings that can be provided to an
// HTML5 input form field of type date & time respectively. Format will be
// ['2020-12-15', '01:27:36'].
function getHTML5DateTimeStringsFromDate(d) {
// Date string
let ds = d.getFullYear().toString().padStart(4, '0') + '-' + (d.getMonth()+1).toString().padStart(2, '0') + '-' + d.getDate().toString().padStart(2, '0');
// Time string
let ts = d.getHours().toString().padStart(2, '0') + ':' + d.getMinutes().toString().padStart(2, '0') + ':' + d.getSeconds().toString().padStart(2, '0');
// Return them in array
return [ds, ts];
}
// Date object
let d = new Date();
// Get HTML5-ready value strings
let dstrings = getHTML5DateTimeStringsFromDate(d);
// Populate date & time field values
document.getElementById('date').value = dstrings[0]
document.getElementById('time').value = dstrings[1]
/* Or if you want to use jQuery...
$('#date').val(dstrings[0]);
$('#time').val(dstrings[1]);
*/
<input type='date' id='date'>
<input type='time' id='time' step="1">
Thank you j08691. That link was the answer.
To others struggling like me, when they say input is "yyyy-mm-dd" the MEAN it!
You MUST have 4 digits for the year.
You MUST have a dash and no spaces.
You MUST have 2 digits for day and month.
In my example myDate.getMonth for January would only return "1" (actually it returns "0" because for some reason javascript counts months from 0-11). To get this right I had to do the following:
var myDate, day, month, year, date;
myDate = new Date();
day = myDate.getDate();
if (day <10)
day = "0" + day;
month = myDate.getMonth() + 1;
if (month < 10)
month = "0" + month;
year = myDate.getYear();
date = year + "-" + month + "-" + day;
$("#date").val(date);
I hope this helps others not waste hours like I did testing this before October or before the 10th of the month! LOL
Here is an answer based on Robin Drexlers but in local time.
//Get the local date in ISO format
var date = new Date();
date.setMinutes(date.getMinutes() - date.getTimezoneOffset());
var datestr = date.toISOString().substring(0, 10);
//Set the field value
var field = document.querySelector('#date');
field.value = datestr;
If it's a datetime field you're modifying (as opposed to just the date) don't forget to add the time T00:00, or change the substring to 16 characters for example:
//Get the local date and time in ISO format
var date = new Date();
date.setMinutes(date.getMinutes() - date.getTimezoneOffset());
var datestr = date.toISOString().substring(0, 16);
//Set the field value
var field = document.querySelector('#datetime');
field.value = datestr;
This below code populates the local date . The accepted answer populates UTC date.
var date = new Date();
field = document.querySelector('#date-id');
var day = date.getDate();
if(day<10){ day="0"+day;}
var month = date.getMonth()+1;
if(month<10){ month="0"+month;}
field.value = date.getFullYear()+"-"+month+"-"+day;
I don't have the reputation points to comment on another answer, so I'll just add a new answer. And since I'm adding an answer, I'll give more details than I would've in a comment.
There's an easier way to zero pad than all of the juggling that everyone is doing here.
var date = new Date();
var month = ('0' + (date.getMonth() + 1)).slice(-2);
var day = ('0' + date.getDate()).slice(-2);
var year = date.getFullYear();
var htmlDate = year + '-' + month + '-' + day;
console.log("Date: " + htmlDate);
Today, the output would be
Date: 2020-01-07
The code is building a dynamic string by prepending a quoted zero, then taking the last 2 characters with slice(-2). This way, if the zero makes it 01, the last 2 are 01. If the zero makes it 011, then the last two are 11.
As for the month starting at zero silliness, you can also add 1 dynamically before prepending the zero and everything still works. You just have to do the math operation before turning it into a string.
As a side note, I've noticed that when you update a date field, you have to hide the field before setting the value and show it after setting. I don't do this often enough, so I have to re-struggle each time I need to deal with it. Hopefully this will help someone from the future.
waves to future people
I need to know the date for last Sunday for given date in php & javascript
Let's have a function give_me_last_Sunday
give_me_last_Sunday('20110517') is 20110515
give_me_last_Sunday('20110604') is 20110529
The full backup is done on Sundays = weekly. If I want to restore daily backup I need full (weekly) and daily backup. I need to copy backup files before restoring to temp directory so I restoring daily backup I need to know what weekly backup file I need to copy along the daily file.
My thought was to get Julian representation (or something similar) for the given date and then subtract 1 and check if it is Sunday ... Not sure if this is the best idea and how to convert given date into something I can subtract.
Based on Thomas' effort, and provided the input string is exactly the format you specified, then:
function lastSunday(d) {
var d = d.replace(/(^\d{4})(\d{2})(\d{2}$)/,'$1/$2/$3');
d = new Date(d);
d.setDate(d.getDate() - d.getDay());
return d;
}
Edit
If I were to write that now, I'd not depend on the Date object parsing the string but do it myself:
function lastSunday(s) {
var d = new Date(s.substring(0,4), s.substring(4,6) - 1, s.substring(6));
d.setDate(d.getDate() - d.getDay());
return d;
}
While the format yyyy/mm/dd is parsed correctly by all browsers I've tested, I think it's more robust to stick to basic methods. Particularly when they are likely more efficient.
Ok so this is for JavaScript only. You have an input that you need to extract the month, date, and year from. The following is just partly an answer then on how to get the date:
<script type="text/javascript">
var myDate=new Date();
myDate.setFullYear(2011,4,16)
var a = myDate.getDate();
var t = myDate.getDay();
var r = a - t;
document.write("The date last Sunday was " + r);
</script>
So the setFullYear function sets the myDate to the date specified where the first four digits is the year, the next are is the month (0= Jan, 1= Feb.,...). The last one is the actually date. Then the above code gives you the date of the Sunday before that. I am guessing that you can add more code to get the month (use getMonth() method). Here are a few links that might be helpful
http://www.w3schools.com/js/js_obj_date.asp
http://www.w3schools.com/jsref/jsref_setFullYear.asp
http://www.w3schools.com/jsref/jsref_getMonth.asp
(You can probably find the other functions that you need)
I hope this helps a bit even though it is not a complete answer.
Yup and strtotime has been ported to JS for eg http://phpjs.org/functions/strtotime:554 here.
final code (big thanks to #Thomas & #Rob)
function lastSunday(d) {
var d = d.replace(/(^\d{4})(\d{2})(\d{2}$)/,'$1/$2/$3');
d = new Date(d);
d.setDate(d.getDate() - d.getDay());
year = d.getFullYear()+'';
month = d.getMonth()+1+'';
day = d.getDate()+'';
if ( month.length == 1 ) month = "0" + month; // Add leading zeros to month and date if required
if ( day.length == 1 ) day = "0" + day;
return year+month+day;
}