I have two dates 18-Aug-2010 and 19-Aug-2010 of this format. How to find whether which date is greater?
You will need to create a custom parsing function to handle the format you want, and get date objects to compare, for example:
function customParse(str) {
var months = ['Jan','Feb','Mar','Apr','May','Jun',
'Jul','Aug','Sep','Oct','Nov','Dec'],
n = months.length, re = /(\d{2})-([a-z]{3})-(\d{4})/i, matches;
while(n--) { months[months[n]]=n; } // map month names to their index :)
matches = str.match(re); // extract date parts from string
return new Date(matches[3], months[matches[2]], matches[1]);
}
customParse("18-Aug-2010");
// "Wed Aug 18 2010 00:00:00"
customParse("19-Aug-2010") > customParse("18-Aug-2010");
// true
You can do the parsing manually, for your given format, but I'd suggest you use the date.js library to parse the dates to Date objects and then compare.
Check it out, its awesome!
And moreover, its a great addition to your js utility toolbox.
The native Date can parse "MMM+ dd yyyy", which gives:
function parseDMY(s){
return new Date(s.replace(/^(\d+)\W+(\w+)\W+/, '$2 $1 '));
}
+parseDMY('19-August-2010') == +new Date(2010, 7, 19) // true
parseDMY('18-Aug-2010') < parseDMY('19-Aug-2010') // true
Firstly, the 'dd-MMM-yyyy' format isn't an accepted input format of the Date constructor (it returns an "invalid date" object) so we need to parse this ourselves. Let's write a function to return a Date object from a string in this format.
function parseMyDate(s) {
var m = ['jan','feb','mar','apr','may','jun','jul','aug','sep','oct','nov','dec'];
var match = s.match(/(\d+)-([^.]+)-(\d+)/);
var date = match[1];
var monthText = match[2];
var year = match[3];
var month = m.indexOf(monthText.toLowerCase());
return new Date(year, month, date);
}
Date objects implicitly typecast to a number (milliseconds since 1970; epoch time) so you can compare using normal comparison operators:
if (parseMyDate(date1) > parseMyDate(date2)) ...
Update: IE10, FX30 (and likely more) will understand "18 Aug 2010" without the dashes - Chrome handles either
so Date.parse("18-Aug-2010".replace("/-/g," ")) works in these browsers (and more)
Live Demo
Hence
function compareDates(str1,str2) {
var d1 = Date.parse(str1.replace("/-/g," ")),
d2 = Date.parse(str2.replace("/-/g," "));
return d1<d2;
}
Related
I am trying to create an if statement that can check today's date and time and if it's greater than a predefined date and time, do something. I'm looking to do this in vanilla JS only and get it to work in IE.
This is the basic working code for Chrome.
var ToDate = new Date()
if (new Date("2018-11-30 05:00").getTime() > ToDate.getTime()) {
alert("true")
} else {
alert("false")
}
How can I make something like this work in IE?
if (new Date("2018-11-30 05:00").getTime() > ToDate.getTime()) {
On firefox and chrome there are no issues with it. On Internet Explorer it's false.
On IE (or in general) the string needs to be an RFC2822 or ISO 8601 formatted date
Example:
new Date("2018-11-29T19:15:00.000Z")
If you need portable solution (eg. support older Internet Explorer) I would use this constructor instead:
new Date(year, monthIndex [, day [, hours [, minutes [, seconds [, milliseconds]]]]]);
Keep in mind that monthIndex starts from 0 (January).
Test:
function assertTrue(exp, message) {
if (exp === false) {
message = message || 'Assertion failed';
alert(message);
throw message;
}
}
function testShouldPassForDatesInTheFuture() {
var ToDate = new Date(2018, 10, 29);
assertTrue(new Date(2018, 10, 30).getTime() > ToDate.getTime());
}
function testShouldPassForDatesInThePast() {
var ToDate = new Date(2018, 10, 29);
assertTrue(new Date(2018, 10, 28).getTime() < ToDate.getTime());
}
testShouldPassForDatesInThePast();
testShouldPassForDatesInThePast();
alert('All test passed');
You need to append 'T00:00:00.000Z' to your date.
new Date("2018-11-30" + 'T00:00:00.000Z')
Full code is below:
var ToDate = new Date()
if (new Date("2018-11-30" + 'T00:00:00.000Z').getTime() > ToDate.getTime()) {
alert("true")
} else {
alert("false")
}
Your issue is that the date format YYYY-MM-DD HH:mm is not supported by ECMAScript, so parsing is implementation dependent. Safari, for example:
new Date("2018-11-30 05:00")
returns an invalid date.
You can first parse the string manually, either with a bespoke function (e.g. How to parse a string into a date object at JavaScript?) or a library, then you can compare the result with new Date() as for Compare two dates with JavaScript.
A simple parse function is not difficult:
/* Parse string in YYYY-MM-DD HH:mm:ss to a Date
* All parts after YYYY-MM are optional, milliseconds ignored
*/
function parseDate(s) {
var b = s.split(/\D/);
return new Date(b[0], b[1]-1, b[2]||1, b[3]||0, b[4]||0, b[5]||0);
}
["2018-11-23 17:23",
"2019-01",
"2020-12-31 23:59:59"].forEach(s => {
console.log(`${s} => ${parseDate(s).toString()}`);
});
Then you can compare dates using <, <=, > and >=.
In this case, a date like "2018-01-01" will be considered past at any time after 2018-01-01 00:00:00.000.
Alternatively, since the string is similar to ISO 8601 format, you can compare the parts of the string with a similarly formatted string for today:
// Return date string in YYYY-MM-DD HH:mm:ss format
// Only return as many parts as len, or all 6 if missing
function formatDate(d, len) {
var parts = [d.getFullYear(), '-'+d.getMonth()+1, '-'+d.getDate(), ' '+d.getHours(), ':'+d.getMinutes(), ':'+d.getSeconds()];
var spacer = ['-','-',' ',':',':'];
len = len || 6;
return parts.splice(0, len).join('');
}
['2018-06-30 12:04',
'2018-10',
'2018-12-15 03:14:45',
'2019-01-01',
'2020-12-15 03:14:45'].forEach(s => {
console.log(`${s} has passed? ${s < formatDate(new Date(), s.split(/\D/).length)}`);
});
In this case, 2018-01-01 will be equal to any date generated on that day, and "2018-01" will be equal to any date generated in January 2018. It's up to you whether you use < or <= for the comparison.
So you need to consider carefully where you draw the boundary between earlier and later and adjust the logic accordingly.
I have 2 dates which I need to compare to see if one is greater than the other but they are in different formats and I'm not sure of the best way to compare the 2.
The formats are:
1381308375118 (this is var futureDate)
which is created by
var today = new Date(); today.setHours(0, 0, 0, 0); var futureDate = new Date().setDate(today.getDate() + 56); //56 days in the future...
And the other format is
2013/08/26
Any ideas how I can compare the 2?
Without using a 3rd party library, you can create new Date objects using both those formats, retrieve the number of milliseconds (since midnight Jan 1, 1970) using getTime() and then simply use >:
new Date("2013/08/26").getTime() > new Date(1381308375118).getTime()
I strongly recommend using datejs library.
Thus this can be written in one single line:
Date.today().isAfter(Date.parse('2013/08/26'))
I would make sure that I am comparing the "date" element of each format and exclude any "time" element. Then with both dates converted to milliseconds, simply compare the values. You could do something like this. If dates are equal it returns 0, if the first date is less that the second then return -1, otherwise return 1.
Javascript
function compareDates(milliSeconds, dateString) {
var year,
month,
day,
tempDate1,
tempDate2,
parts;
tempDate1 = new Date(milliSeconds);
year = tempDate1.getFullYear();
month = tempDate1.getDate();
day = tempDate1.getDay();
tempDate1 = new Date(year, month, day).getTime();
parts = dateString.split("/");
tempDate2 = new Date(parts[0], parts[1] - 1, parts[2]).getTime();
if (tempDate1 === tempDate2) {
return 0;
}
if (tempDate1 < tempDate2) {
return -1;
}
return 1;
}
var format1 = 1381308375118,
format2 = "2013/08/26";
console.log(compareDates(format1, format2));
On jsfiddle
Maybe you can use Date.parse("2013/08/26") and compare with former one
Follow these steps to compare dates
Each of your date must to passed through Date object i.e. new Date(yourDate).
Now dates will have same format and these will be comparable
let date1 = new Date()
let date2 = "Jan 1, 2019"
console.log(`Date 1: ${date1}`)
console.log(`Date 2: ${date2}`)
let first_date = new Date(date1)
let second_date = new Date(date2)
// pass each of the date to 'new Date(yourDate)'
// and get the similar format dates
console.log(`first Date: ${first_date}`)
console.log(`second Date: ${second_date}`)
// now these dates are comparable
if(first_date > second_date) {
console.log(`${date2} has been passed`)
}
Is there any way to get system short date format in JavaScript?
For example whether system's short date is in American format eg. m/d/Y or in european eg. d/m/Y
Please note:
This is not question about formatting date or calculating it based on geolocation, but about getting the format from the OS/system
After a pinch of research I concluded that technically it's not possible to get regional settings -and by this, date format- but you can do several other things. Pick one of these options:a) The already mentioned -and outdated- "toLocaleString()" function:
var myDate = new Date(1950, 01, 21, 22, 23, 24, 225);
var myDateFormat = myDate.toLocaleString();
alert (myDateFormat);
ISSUES:1) You can't "myDateFormat.replace" to get the date mask as month is not stored as "01", "02", etc in the string but as text instead, based on locale (like "February" in English but it's "Φεβρουάριος" in Greek and who knows what in e.g. Klingon).2) Different behavior on different browsers3) Different behavior on different OS and browser versions...b) Use the toISOString() function instead of toLocaleString(). You won't get the locale date mask but get a date from which you can tell where's which part of the date (ie where "month" or "day" is in that string). You can also work with getUTCDate(), getUTCMonth() and getUTCDay() functions. You still can't tell what date format the client uses, but can tell which Year/Month/Day/etc you work with when you grab a date; use the code above to test the functions I mentioned here to see what you can expect.c) Read
Inconsistent behavior of toLocaleString() in different browser article and use the (IMHO great) solution described there
for my case i used a custom date that i know what number is day, what is month and what is year so it can possible with a simple replace statement.
let customDate = new Date(2222, 11, 18);
let strDate = customDate.toLocaleDateString();
let format = strDate
.replace("12", "MM")
.replace("18", "DD")
.replace("2222", "yyyy");
It is not possible. You can get culture from user browser and use some js libraries to convert to correct date format. http://code.google.com/p/datejs/
I made a function to determine the client date format. The function determine
the date format separator, and also determine the 1st, 2nd and third part of
the date format.
getDateFormat(){
// initialize date value "31st January 2019"
var my_date = new Date(2019,0,31);
console.log(my_date.toLocaleDateString());
// Initialize variables
var separator="";
var first="";
var second="";
var third="";
var date_parts = [];
// get separator : "-", "/" or " ", format based on toLocaleDateString function
if (my_date.toLocaleDateString().split("-").length==3){
separator = " - ";
date_parts = my_date.toLocaleDateString().split("-");
}
if (my_date.toLocaleDateString().split("/").length == 3) {
separator = " / ";
date_parts = my_date.toLocaleDateString().split("/");
}
if (my_date.toLocaleDateString().split(" ").length == 3) {
separator = " ";
date_parts = my_date.toLocaleDateString().split(" ");
}
// get first part
if (date_parts[0]==2019){
first ="yyyy";
} else if (date_parts[0] == 31){
first = "dd";
} else{
if (date_parts[0].length<=2){
first ="mm";
}
else{
first="mmm";
}
}
// get second part
if (date_parts[1] == 2019) {
second = "yyyy";
} else if (date_parts[1] == 31) {
second = "dd";
} else {
if (date_parts[1].length <= 2) {
second = "mm";
}
else {
second = "mmm";
}
}
// get third part
if (date_parts[2] == 2019) {
third = "yyyy";
} else if (date_parts[2] == 31) {
third = "dd";
} else {
if (date_parts[2].length <= 2) {
third = "mm";
}
else {
third = "mmm";
}
}
// assembly
var format = first + separator + second + separator + third;
console.log(format);
return format;
}
I've created a workaround to determine which format the user's browser is using.
This is in C# but the logic is the same:
Here are the steps:
First try to convert the user's browser date into American format (mm-dd-yyyy). Convert.ToDateTime is using the American date format.
If that fails it means the user is using European format (dd-mm-yyyy).
However, this will only cover the day 13 to 31 because this is not a valid month.
If the conversion is successful, do another check to determine if the converted date is between the current UTC day + 1 day (to cover UTC+14) and current UTC day - 1 day (to cover UTC-12).
https://www.timeanddate.com/time/current-number-time-zones.html
If the converted date is out of the current date range, it means the user's browser is using European format (dd-mm-yyyy) and you can convert it to American format if you want.
string localeDateString = "01/11/2020"; // e.g. input is using European format (dd-mm-yyyy)
var localeDate = new DateTime();
try
{
localeDate = Convert.ToDateTime(localeDateString);
//var checkTheFormatOfDateInput = localeDate.ToLongDateString();
var currentDateTime = DateTime.UtcNow;
//var currentDateTime = Convert.ToDateTime("11/01/2020");
//var checkTheFormatOfCurrentDate = Convert.ToDateTime("11/01/2020").ToLongDateString();
var currentDateTimePositive = currentDateTime.AddDays(1);
var currentDateTimeNegative = currentDateTime.AddDays(-1);
var outOfCurrentDateRange = !(localeDate.Ticks > currentDateTimeNegative.Ticks && localeDate.Ticks < currentDateTimePositive.Ticks);
if (outOfCurrentDateRange)
{
localeDate = DateTime.ParseExact(localeDateString, "dd/MM/yyyy", CultureInfo.InvariantCulture);
}
}
catch
{
localeDate = DateTime.ParseExact(localeDateString, "dd/MM/yyyy", CultureInfo.InvariantCulture);
}
//var checkTheEndResultFormat = localeDate.ToLongDateString();
Below is the clean code wrapped in a method:
private DateTime ConvertAmericanOrEuropeanDateFormatToAmericanDateFormat(string localeDateString)
{
var localeDate = new DateTime();
try
{
localeDate = Convert.ToDateTime(localeDateString);
var currentDateTime = DateTime.UtcNow;
var currentDateTimePositive = currentDateTime.AddDays(1);
var currentDateTimeNegative = currentDateTime.AddDays(-1);
var outOfCurrentDateRange = !(localeDate.Ticks > currentDateTimeNegative.Ticks && localeDate.Ticks < currentDateTimePositive.Ticks);
if (outOfCurrentDateRange)
{
localeDate = DateTime.ParseExact(localeDateString, "dd/MM/yyyy", CultureInfo.InvariantCulture);
}
}
catch
{
localeDate = DateTime.ParseExact(localeDateString, "dd/MM/yyyy", CultureInfo.InvariantCulture);
}
return localeDate;
}
A very good but lengthy answer can here found here: https://stackoverflow.com/a/9893752/2484903
A shorter one here:
let customDate = new Date(2222, 3, 8);
let strDate = customDate.toLocaleDateString();
let format = strDate
.replace("04", "MM")
.replace("4", "M")
.replace("08", "dd")
.replace("8", "d")
.replace("2222", "yyyy")
.replace("22", "yy");
console.log(format);
We create a date object of a known date and then parse the outcome.
First we look for "04" (which corresponds to 3 from the date definition); that would be the two digit month format MM. If not found, it must be the single digit format M. Afterwards do the same for day and year.
It should do the job...
function getSystemDateLocale(){
let testDate = (new Date('2000-1-30')).toLocaleDateString()
if (testDate.substring(0,2) == '30') return 'EU'
else return 'US'
}
Use Date.CultureInfo.formatPatterns.shortDate
I need to validate different date's with some javascript(jquery).
I have a textbox with, the inputmask from jquery (http://plugins.jquery.com/plugin-tags/inputmask). The mask that i use is "d/m/y".
Now i have set up a CustomValidator function to validate the date.
I need 2 functions. One to check if the given date is greater then 18 years ago. You must be older then 18 year.
One function to check if the date is not in the future. It can only in the past.
The function are like
function OlderThen18(source, args) {
}
function DateInThePast(source, args) {
}
As you know the value you get back with args.Value is 27/12/1987 .
But how can i check this date in the functions? So that i can set args.IsValid to True or False.
I tried to parse the string(27/12/1987) that i get back from the masked textbox to a date but i get always a value back like 27/12/1988.
So how could I check the given dates with the other dates?
The simple way is to add 18 years to the supplied date and see if the result is today or earlier, e.g.:
// Input date as d/m/y or date object
// Return true/false if d is 18 years or more ago
function isOver18(d) {
var t;
var now = new Date();
// Set hours, mins, secs to zero
now.setHours(0,0,0);
// Deal with string input
if (typeof d == 'string') {
t = d.split('/');
d = new Date(t[2] + '/' + t[1] + '/' + t[0]);
}
// Add 18 years to date, check if on or before today
if (d.setYear && d.getFullYear) {
d.setYear(d.getFullYear() + 18);
}
return d <= now;
}
// For 27/4/2011
isOver18('27/4/2011'); // true
isOver18('26/4/2011'); // true
isOver18('28/4/2011'); // false
try this to start:
var d = new Date(myDate);
var now = new Date();
if ((now.getFullYear() - d.getFullYear()) < 18) {
//do stuff
}
The javascript date object is quite flexible and can handle many date strings.
You can compare two Date objects or use the Date interface methods, such as getSeconds() of getFullYear() in order to deduce useful data regarding the date.
See Date object reference formore details.
You'll need to construct, modify and compare Date objects - something like this:
// str should already be in dd/mm/yyyy format
function parseDate(str) {
var a = str.split('/');
return new Date(parseInt(a[2], 10), // year
parseInt(a[1], 10) - 1, // month, should be 0-11
parseInt(a[0], 10)); // day
}
// returns a date object for today (at midnight)
function today() {
var date = new Date();
date.setHours(0, 0, 0);
return date;
}
function DateInThePast(str) {
// date objects can be compared like numbers
// for equality (==) you'll need to compare the value of date.getTime()
return parseDate(str) < today();
}
function OlderThan18(str) {
// left as an exercise for the reader :-)
}
How would I achieve the pseudo-code below in JavaScript? I want to include the date check in the second code excerpt, where txtDate is for the BilledDate.
If ABS(billeddate – getdate) > 31 then yesno “The date you have entered is more than a month from today, Are you sure the date is correct,”.
if (txtDate && txtDate.value == "")
{
txtDate.focus();
alert("Please enter a date in the 'Date' field.")
return false;
}
Generally speaking you work with Date-objects in javascript, and these should be constructed with the following syntax:
var myDate = new Date(yearno, monthno-1, dayno);
//you could put hour, minute, second and milliseconds in this too
Beware, the month-part is an index, so january is 0, february is 1 and december is 11 !-)
Then you can pull out anything you want, the .getTime() thing returns number of milliseconds since start of Unix-age, 1/1 1970 00:00, så this value you could subtract and then look if that value is greater than what you want:
//today (right now !-) can be constructed by an empty constructor
var today = new Date();
var olddate = new Date(2008,9,2);
var diff = today.getTime() - olddate.getTime();
var diffInDays = diff/(1000*60*60*24);//24 hours of 60 minutes of 60 second of 1000 milliseconds
alert(diffInDays);
This will return a decimal number, so probably you'll want to look at the integer-value:
alert(Math.floor(diffInDays));
To get the date difference in days in plain JavaScript, you can do it like this:
var billeddate = Date.parse("2008/10/27");
var getdate = Date.parse("2008/09/25");
var differenceInDays = (billeddate - getdate)/(1000*60*60*24)
However if you want to get more control in your date manipulation I suggest you to use a date library, I like DateJS, it's really good to parse and manipulate dates in many formats, and it's really syntactic sugar:
// What date is next thrusday?
Date.today().next().thursday();
//or
Date.parse('next thursday');
// Add 3 days to Today
Date.today().add(3).days();
// Is today Friday?
Date.today().is().friday();
// Number fun
(3).days().ago();
You can use this to check for valid date
function IsDate(testValue) {
var returnValue = false;
var testDate;
try {
testDate = new Date(testValue);
if (!isNaN(testDate)) {
returnValue = true;
}
else {
returnValue = false;
}
}
catch (e) {
returnValue = false;
}
return returnValue;
}
And this is how you can manipulate JS dates. You basically create a date object of now (getDate), add 31 days and compare it to the date entered
function IsMoreThan31Days(dateToTest) {
if(IsDate(futureDate)) {
var futureDateObj = new Date();
var enteredDateObj = new Date(dateToTest);
futureDateObj.setDate(futureDateObj.getDate() + 31); //sets to 31 days from now.
//adds hours and minutes to dateToTest so that the test for 31 days is more accurate.
enteredDateObj.setHours(futureDateObj.getHours());
enteredDateObj.setMinutes(futureDateObj.getMinutes() + 1);
if(enteredDateObj >= futureDateObj) {
return true;
}
else {
return false;
}
}
}
Hello and good day for everyone
You can try Refular Expressions to parse and validate a date format
here is an URL yoy can watch some samples and how to use
http://www.javascriptkit.com/jsref/regexp.shtml
A very very simple pattern would be: \d{2}/\d{2}/\d{4}
for MM/dd/yyyy or dd/MM/yyyy
With no more....
bye bye