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;
}
Related
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;
}
How do I verify in jQuery that a date entered on a input text box or value in html such as mm/dd/yyyy is not greater than todays date. Example would be "5/5/2011" would pass as true b/c its not greater than today "6/17/2011", but "5/5/3011" would be greater than today and should return false. Is there a simple function that can return true or false if a date in form "mm/dd/yyyy" is greater than todays date in javascript or jQuery?
Just convert to a Date object and compare your date value to Date.now - for example:
alert( Date.parse("3/1/2012") > Date.now())
You do not actually need to use jQuery for this at all, pure JavaScript is good enough. Please have a look at the docs for Javascript Date for more information.
convert to javascript Date objects to compare.
var d = new Date("5/5/2011")
var d2 = new Date()
var b = d < d2 // << true...
First off, you need to be sure that dates have a universal format. 10/1/2011 is in the future in the US (October 1st, 2011) but in the past in the UK (10th January 2011). If that's satisfied, the below will work just fine:
function greaterThanToday(datestring) {
var today = new Date();
var date = new Date(datestring);
return (date > today);
}
alert("5/5/2011: " + greaterThanToday("5/5/2011"));
alert("5/5/3011: " + greaterThanToday("5/5/3011"));
Don't even need jQuery, just Date objects.
Date.parse("6/17/2011") > Date.parse("5/5/3011")
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);
I was playing around with Javascript creating a simple countdown clock when I came across this strange behavior:
var a = new Date(),
now = a.getTime(),
then = Date.UTC(2009,10,31),
diff = then - now,
daysleft = parseInt(diff/(24*60*60*1000));
console.log(daysleft );
The days left is off by 30 days.
What is wrong with this code?
Edit: I changed the variable names to make it more clear.
The month is zero-based for JavaScript.
Days and years are one-based.
Go figure.
UPDATE
The reason this is so, from the creator of JavaScript, is
JS had to "look like Java" only less so, be Java's dumb kid brother or boy-hostage sidekick. Plus, I had to be done in ten days or something worse than JS would have happened.
http://www.jwz.org/blog/2010/10/every-day-i-learn-something-new-and-stupid/#comment-1021
As Eric said, this is due to months being listed as 0-11 range.
This is a common behavior - same is true of Perl results from localtime(), and probably many other languages.
This is likely originally inherited from Unix's localtime() call.
(do "man localtime")
The reason is that days/years are their own integers, while months (as a #) are indexes of an array, which in most languages - especially C where the underlying call is implemented on Unix - starts with 0.
It's an old question but this is still a problem today (or a feature as some might say - and they are wrong).
JS is zero-based month, why? Because.
That means the months range from 0-11 (only the months, the others are normal)
How can you fix this? Add a month, obviously, BUUUUT:
Don't do this :
let date: Date = new Date();
date.setMonth(date.getMonth() + 1);
Why you might ask? Because it won't work as expected, Date in JS is terrible.
You have to make a ... let's call it not so beautiful function to translate the JS date to a normal date
formatJsDateToNormalDate(Date date): string | null {
if(date !== null) {
const realMonth: number = date.getMonth() + 1;
let month: string = (realMonth < 10) ? '0' + realMonth : String(realMonth);
let day: string = (date.getDate() < 10) ? '0' + date.getDate() : String(date.getDate());
return [date.getFullYear(), month, day].join('-');
} else {
return null;
}
Again, if you ask me this is the equivalent of hammering a screw, it's not the right way, but there is no right way here, it's a bug that has been going on for 27 years and more to come.
date1 = new Date();
//year, month, day [, hrs] [, min] [, sec]
date1 = new Date.UTC(date1.getFullYear(),date1.getMonth()+1,date1.getDate(),date1.getHours(),date1.getMinutes(),date1.getSeconds());
date2 = new Date();
date2 = date2.getTime();
alert(date1)
alert(date2)