Javascript - Regex to validate date format

Question

Is there any way to have a regex in JavaScript that validates dates of multiple formats, like: DD-MM-YYYY or DD.MM.YYYY or DD/MM/YYYY etc? I need all these in one regex and I'm not really good with it. So far I've come up with this: var dateReg = /^\d{2}-\d{2}-\d{4}$/; for DD-MM-YYYY. I only need to validate the date format, not the date itself.

If the only thing that varies is the separator then replace the `-` with `[\-\/\.]` (or whatever the escaping would be). — Dave Newton, Sep 12 '11 at 12:42
It's your own custom format date string. International formats is: dd.mm.yyyy or mm/dd/yyyy or yyyy-mm-dd. — Andrew D., Sep 12 '11 at 13:27
This is the BEST answer, no ugly Regex and such: http://stackoverflow.com/questions/5774931/javascript-regular-expression-to-validate-date/5775146#5775146 — vsync, Nov 14 '11 at 13:14
Please consider reassigning the correct answer. Current answer matches incorrect dates (99-99-9999, etc..). Thanks! — Dropout, Dec 09 '15 at 07:40
@Dropout I've instead edited the question, to specify that I only needed to validate the format, not the actual date validity. If that were the case, @nicoabie's answer would have been better, even though it says `01.01-2015` is valid, so none of the answers correctly fully validate a date. Thanks for pointing this out, though. — Eduard Luca, Dec 09 '15 at 11:01
@EduardLuca OK great, thank you too! just trying to make things more helpful for others which come to the question later ;) cheers! — Dropout, Dec 09 '15 at 12:14

score 44 · Accepted Answer · answered Sep 12 '11 at 12:42

44

You could use a character class ([./-]) so that the seperators can be any of the defined characters

var dateReg = /^\d{2}[./-]\d{2}[./-]\d{4}$/

Or better still, match the character class for the first seperator, then capture that as a group ([./-]) and use a reference to the captured group \1 to match the second seperator, which will ensure that both seperators are the same:

var dateReg = /^\d{2}([./-])\d{2}\1\d{4}$/

"22-03-1981".match(dateReg) // matches
"22.03-1981".match(dateReg) // does not match
"22.03.1981".match(dateReg) // matches

answered Sep 12 '11 at 12:42

Billy Moon

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1

thanks. other than the slash "/" not being escaped correctly, it works fine. – Eduard Luca Sep 12 '11 at 12:57
I don't think the slash needs to be escaped inside a character class, but there is no harm in escaping it if you want to. Might make the syntax hilighting in your text editor work better, but should work either way. – Billy Moon Sep 12 '11 at 13:02
can you add a limitation for the first number (month) not to be over '3'? – vsync Nov 13 '11 at 10:03
try `var dateReg = /^0[123]([./-])\d{2}\1\d{4}$/` – Billy Moon Nov 13 '11 at 12:30
or simply you can use this https://www.npmjs.com/package/raysk-vali for date validation and more. – Ravi Singh Jan 15 '20 at 11:44

score 21 · Answer 2 · edited Oct 24 '12 at 19:11

21

Format, days, months and year:

var regex = /^(0[1-9]|[12][0-9]|3[01])[- /.](0[1-9]|1[012])[- /.](19|20)\d\d$/;

edited Oct 24 '12 at 19:11

David Hoerster

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answered Oct 24 '12 at 18:51

nicoabie

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This partially validates the date, but still allows for dates like `30-02-2013` which is invalid. More complex rules are needed to account for different month lengths. – Billy Moon Mar 18 '13 at 11:44
3

Technically speaking @BillyMoon, we are actually validating its format, not the date itself. Yours allows dates like 30-02-2013 too my friend. – nicoabie Mar 18 '13 at 20:03
Yes, mine is designed to extract the numbers from valid dates, and does not attempt to do validation, which yours does. I think with some adjustment, you could have reasonable validation of dates, which I would like to see you do, but half validating them seems to me like having a weak fence on a cliff edge, better to have none at all, lest someone leans on it! Better still to have a strong one. – Billy Moon Mar 18 '13 at 20:25
@BillyMoon `Format, days, months and year:`, what are you talking about? – Dropout Dec 09 '15 at 08:33
@Dropout - is your question aimed at @nicoabie? – Billy Moon Dec 09 '15 at 18:13
@BillyMoon oh, sorry I thought you were talking about MM-DD-YYYY being an invalid format, now I noticed it's 30th Feb. My bad, sorry. – Dropout Dec 10 '15 at 06:28

mplungjan · Answer 3 · 2023-01-11T17:57:59.397

13

The suggested regex will not validate the date, only the pattern.

So 99.99.9999 will pass the regex.

You later specified that you only need to validate the pattern but I still think it is more useful to create a date object

const isDDMMYYYY = str => {
  let [dd, mm, yyyy] = str.split(/[\.\-\/]/); // change to suit your locale
  dd = +dd;     // cast to number
  yyyy = +yyyy; // cast to number
  let mm0 = mm - 1, // js months are 0 based
    date = new Date(yyyy, mm0, dd, 15, 0, 0, 0); // normalise
  return mm0 === date.getMonth() && dd === date.getDate() && yyyy === date.getFullYear();
};
const dates = [
  "13-01-2023",
  "13.01.2023",
  "13/01/2023",
  "08-08-1991",
  "29/02/2011"
];

dates.forEach(date => console.log(date, ':', isDDMMYYYY(date)));

edited Jan 11 '23 at 17:57

answered Sep 12 '11 at 12:43

mplungjan

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the validation of invalid date values will be done by me manually. if i enter something like 08-08-1991 with your solution, would get me an "Invalid Date" in javascript for some reason. – Eduard Luca Sep 12 '11 at 12:59
1

Not in Fx : I added that date to http://jsfiddle.net/mplungjan/Mqh8D/ What browser are you one? – mplungjan Sep 12 '11 at 19:43
If you use parseInt you MUST use the radix 10 since 08 and 09 are invalid octal numbers – mplungjan Sep 28 '12 at 16:07
Why do you increment and decrement the months ? See: `var date = new Date(yyyy,mm-1,dd,0,0,0,0);` (`(date.getMonth()+1)`) – Ndrslmpk May 17 '22 at 11:13
Js months are 0 based - I can decrement the month in the constructor or increment in the comparison – mplungjan May 17 '22 at 11:17

score 10 · Answer 4 · edited Jul 08 '14 at 10:29

You can use regular multiple expressions with the use of OR (|) operator.

function validateDate(date){
    var regex=new RegExp("([0-9]{4}[-](0[1-9]|1[0-2])[-]([0-2]{1}[0-9]{1}|3[0-1]{1})|([0-2]{1}[0-9]{1}|3[0-1]{1})[-](0[1-9]|1[0-2])[-][0-9]{4})");
    var dateOk=regex.test(date);
    if(dateOk){
        alert("Ok");
    }else{
        alert("not Ok");
    }
}

Above function can validate YYYY-MM-DD, DD-MM-YYYY date formats. You can simply extend the regular expression to validate any date format. Assume you want to validate YYYY/MM/DD, just replace "[-]" with "[-|/]". This expression can validate dates to 31, months to 12. But leap years and months ends with 30 days are not validated.

score 5 · Answer 5 · answered Sep 12 '11 at 12:41

5

Make use of brackets /^\d{2}[.-/]\d{2}[.-/]\d{4}$/ http://download.oracle.com/javase/tutorial/essential/regex/char_classes.html

answered Sep 12 '11 at 12:41

Simon

860
7
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I'll vote you up as you gave a more succinct version of mine – m.edmondson Sep 12 '11 at 12:42

score 1 · Answer 6 · answered Apr 30 '16 at 15:48

Please find in the below code which enables to perform the date validation for any of the supplied format or based on user locale to validate start/from and end/to dates. There could be some better approaches but have come up with this. Have tested it for the formats like: MM/dd/yyyy, dd/MM/yyyy, yyyy-MM-dd, yyyy.MM.dd, yyyy/MM/dd and dd-MM-yyyy.

Note supplied date format and date string go hand in hand.

    <script type="text/javascript">
function validate(format) {

    if(isAfterCurrentDate(document.getElementById('start').value, format)) {
        alert('Date is after the current date.');
    } else {
        alert('Date is not after the current date.');
    }
    if(isBeforeCurrentDate(document.getElementById('start').value, format)) {
        alert('Date is before current date.');
    } else {
        alert('Date is not before current date.');
    }
    if(isCurrentDate(document.getElementById('start').value, format)) {
        alert('Date is current date.');
    } else {
        alert('Date is not a current date.');
    }
    if (isBefore(document.getElementById('start').value, document.getElementById('end').value, format)) {
        alert('Start/Effective Date cannot be greater than End/Expiration Date');
    } else {
        alert('Valid dates...');
    }
    if (isAfter(document.getElementById('start').value, document.getElementById('end').value, format)) {
        alert('End/Expiration Date cannot be less than Start/Effective Date');
    } else {
        alert('Valid dates...');
    }
    if (isEquals(document.getElementById('start').value, document.getElementById('end').value, format)) {
        alert('Dates are equals...');
    } else {
        alert('Dates are not equals...');
    }
    if (isDate(document.getElementById('start').value, format)) {
        alert('Is valid date...');
    } else {
        alert('Is invalid date...');
    }
}

/**
 * This method gets the year index from the supplied format
 */
function getYearIndex(format) {

    var tokens = splitDateFormat(format);

    if (tokens[0] === 'YYYY'
            || tokens[0] === 'yyyy') {
        return 0;
    } else if (tokens[1]=== 'YYYY'
            || tokens[1] === 'yyyy') {
        return 1;
    } else if (tokens[2] === 'YYYY'
            || tokens[2] === 'yyyy') {
        return 2;
    }
    // Returning the default value as -1
    return -1;
}

/**
 * This method returns the year string located at the supplied index
 */
function getYear(date, index) {

    var tokens = splitDateFormat(date);
    return tokens[index];
}

/**
 * This method gets the month index from the supplied format
 */
function getMonthIndex(format) {

    var tokens = splitDateFormat(format);

    if (tokens[0] === 'MM'
            || tokens[0] === 'mm') {
        return 0;
    } else if (tokens[1] === 'MM'
            || tokens[1] === 'mm') {
        return 1;
    } else if (tokens[2] === 'MM'
            || tokens[2] === 'mm') {
        return 2;
    }
    // Returning the default value as -1
    return -1;
}

/**
 * This method returns the month string located at the supplied index
 */
function getMonth(date, index) {

    var tokens = splitDateFormat(date);
    return tokens[index];
}

/**
 * This method gets the date index from the supplied format
 */
function getDateIndex(format) {

    var tokens = splitDateFormat(format);

    if (tokens[0] === 'DD'
            || tokens[0] === 'dd') {
        return 0;
    } else if (tokens[1] === 'DD'
            || tokens[1] === 'dd') {
        return 1;
    } else if (tokens[2] === 'DD'
            || tokens[2] === 'dd') {
        return 2;
    }
    // Returning the default value as -1
    return -1;
}

/**
 * This method returns the date string located at the supplied index
 */
function getDate(date, index) {

    var tokens = splitDateFormat(date);
    return tokens[index];
}

/**
 * This method returns true if date1 is before date2 else return false
 */
function isBefore(date1, date2, format) {
    // Validating if date1 date is greater than the date2 date
    if (new Date(getYear(date1, getYearIndex(format)), 
            getMonth(date1, getMonthIndex(format)) - 1, 
            getDate(date1, getDateIndex(format))).getTime()
        > new Date(getYear(date2, getYearIndex(format)), 
            getMonth(date2, getMonthIndex(format)) - 1, 
            getDate(date2, getDateIndex(format))).getTime()) {
        return true;
    } 
    return false;                
}

/**
 * This method returns true if date1 is after date2 else return false
 */
function isAfter(date1, date2, format) {
    // Validating if date2 date is less than the date1 date
    if (new Date(getYear(date2, getYearIndex(format)), 
            getMonth(date2, getMonthIndex(format)) - 1, 
            getDate(date2, getDateIndex(format))).getTime()
        < new Date(getYear(date1, getYearIndex(format)), 
            getMonth(date1, getMonthIndex(format)) - 1, 
            getDate(date1, getDateIndex(format))).getTime()
        ) {
        return true;
    } 
    return false;                
}

/**
 * This method returns true if date1 is equals to date2 else return false
 */
function isEquals(date1, date2, format) {
    // Validating if date1 date is equals to the date2 date
    if (new Date(getYear(date1, getYearIndex(format)), 
            getMonth(date1, getMonthIndex(format)) - 1, 
            getDate(date1, getDateIndex(format))).getTime()
        === new Date(getYear(date2, getYearIndex(format)), 
            getMonth(date2, getMonthIndex(format)) - 1, 
            getDate(date2, getDateIndex(format))).getTime()) {
        return true;
    } 
    return false;
}

/**
 * This method validates and returns true if the supplied date is 
 * equals to the current date.
 */
function isCurrentDate(date, format) {
    // Validating if the supplied date is the current date
    if (new Date(getYear(date, getYearIndex(format)), 
            getMonth(date, getMonthIndex(format)) - 1, 
            getDate(date, getDateIndex(format))).getTime()
        === new Date(new Date().getFullYear(), 
                new Date().getMonth(), 
                new Date().getDate()).getTime()) {
        return true;
    } 
    return false;                
}

/**
 * This method validates and returns true if the supplied date value 
 * is before the current date.
 */
function isBeforeCurrentDate(date, format) {
    // Validating if the supplied date is before the current date
    if (new Date(getYear(date, getYearIndex(format)), 
            getMonth(date, getMonthIndex(format)) - 1, 
            getDate(date, getDateIndex(format))).getTime()
        < new Date(new Date().getFullYear(), 
                new Date().getMonth(), 
                new Date().getDate()).getTime()) {
        return true;
    } 
    return false;                
}

/**
 * This method validates and returns true if the supplied date value 
 * is after the current date.
 */
function isAfterCurrentDate(date, format) {
    // Validating if the supplied date is before the current date
    if (new Date(getYear(date, getYearIndex(format)), 
            getMonth(date, getMonthIndex(format)) - 1, 
            getDate(date, getDateIndex(format))).getTime()
        > new Date(new Date().getFullYear(),
                new Date().getMonth(), 
                new Date().getDate()).getTime()) {
        return true;
    } 
    return false;                
}

/**
 * This method splits the supplied date OR format based 
 * on non alpha numeric characters in the supplied string.
 */
function splitDateFormat(dateFormat) {
    // Spliting the supplied string based on non characters
    return dateFormat.split(/\W/);
}

/*
 * This method validates if the supplied value is a valid date.
 */
function isDate(date, format) {                
    // Validating if the supplied date string is valid and not a NaN (Not a Number)
    if (!isNaN(new Date(getYear(date, getYearIndex(format)), 
            getMonth(date, getMonthIndex(format)) - 1, 
            getDate(date, getDateIndex(format))))) {                    
        return true;
    } 
    return false;                                      
}

Below is the HTML snippet

    <input type="text" name="start" id="start" size="10" value="05/31/2016" />
    <br/> 
    <input type="text" name="end" id="end" size="10" value="04/28/2016" />
    <br/>
    <input type="button" value="Submit" onclick="javascript:validate('MM/dd/yyyy');" />

Francisco Kahil · Answer 7 · 2013-06-10T17:33:38.307

@mplungjan, @eduard-luca

function isDate(str) {    
    var parms = str.split(/[\.\-\/]/);
    var yyyy = parseInt(parms[2],10);
    var mm   = parseInt(parms[1],10);
    var dd   = parseInt(parms[0],10);
    var date = new Date(yyyy,mm-1,dd,12,0,0,0);
    return mm === (date.getMonth()+1) && 
        dd === date.getDate() && 
        yyyy === date.getFullYear();
}

new Date() uses local time, hour 00:00:00 will show the last day when we have "Summer Time" or "DST (Daylight Saving Time)" events.

Example:

new Date(2010,9,17)
Sat Oct 16 2010 23:00:00 GMT-0300 (BRT)

Another alternative is to use getUTCDate().

score 0 · Answer 8 · answered Mar 13 '15 at 23:15

To make sure it will work, you need to validate it.

function mmIsDate(str) {

    if (str == undefined) { return false; }

    var parms = str.split(/[\.\-\/]/);

    var yyyy = parseInt(parms[2], 10);

    if (yyyy < 1900) { return false; }

    var mm = parseInt(parms[1], 10);
    if (mm < 1 || mm > 12) { return false; }

    var dd = parseInt(parms[0], 10);
    if (dd < 1 || dd > 31) { return false; }

    var dateCheck = new Date(yyyy, mm - 1, dd);
    return (dateCheck.getDate() === dd && (dateCheck.getMonth() === mm - 1) && dateCheck.getFullYear() === yyyy);

};

score 0 · Answer 9 · edited Apr 01 '16 at 12:04

If you want to validate your date(YYYY-MM-DD) along with the comparison it will be use full for you...

    function validateDate()
    {
     var newDate = new Date();
     var presentDate = newDate.getDate();
     var presentMonth = newDate.getMonth();
     var presentYear = newDate.getFullYear();
     var dateOfBirthVal = document.forms[0].dateOfBirth.value;
    if (dateOfBirthVal == null) 
    return false;
    var validatePattern = /^(\d{4})(\/|-)(\d{1,2})(\/|-)(\d{1,2})$/;
    dateValues = dateOfBirthVal.match(validatePattern);
    if (dateValues == null) 
    {
        alert("Date of birth should be null and it should in the format of yyyy-mm-dd")
    return false;
        }
    var birthYear = dateValues[1];        
    birthMonth = dateValues[3];
    birthDate=  dateValues[5];
    if ((birthMonth < 1) || (birthMonth > 12)) 
    {
        alert("Invalid date")
    return false;
        }
    else if ((birthDate < 1) || (birthDate> 31)) 
    {
        alert("Invalid date")
    return false;
        }
    else if ((birthMonth==4 || birthMonth==6 || birthMonth==9 || birthMonth==11) && birthDate ==31) 
    {
        alert("Invalid date")
    return false;
        }
    else if (birthMonth == 2){ 
    var isleap = (birthYear % 4 == 0 && (birthYear % 100 != 0 || birthYear % 400 == 0));
    if (birthDate> 29 || (birthDate ==29 && !isleap)) 
    {
        alert("Invalid date")
    return false;
        }
    }
    else if((birthYear>presentYear)||(birthYear+70<presentYear))
        {
        alert("Invalid date")
        return false;
        }
    else if(birthYear==presentYear)
        {
        if(birthMonth>presentMonth+1)
            {
            alert("Invalid date")
            return false;
            }
        else if(birthMonth==presentMonth+1)
            {
            if(birthDate>presentDate)
                {
                alert("Invalid date")
                return false;
                }
            }
        }
return true;
    }

score 0 · Answer 10 · answered Sep 12 '11 at 12:41

0

Try this:

^\d\d[./-]\d\d[./-]\d\d\d\d$

answered Sep 12 '11 at 12:41

m.edmondson

30,382
27
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score 0 · Answer 11 · answered Sep 12 '11 at 12:43

0

Don't re-invent the wheel. Use a pre-built solution for parsing dates, like http://www.datejs.com/

answered Sep 12 '11 at 12:43

Chris

9,994
3
29
31

3

the reason i don't want to add an external library is that it's not necessary, it would only make the site load slower. but yes, that would have been a solution – Eduard Luca Sep 12 '11 at 12:58

Javascript - Regex to validate date format

11 Answers11

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