Develop Reference

How to get javascript to throw error on bad date input? [duplicate]

I'm trying to test to make sure a date is valid in the sense that if someone enters 2/30/2011 then it should be wrong.
How can I do this with any date?

One simple way to validate a date string is to convert to a date object and test that, e.g.
// Expect input as d/m/y
function isValidDate(s) {
var bits = s.split('/');
var d = new Date(bits[2], bits[1] - 1, bits[0]);
return d && (d.getMonth() + 1) == bits[1];
}
['0/10/2017','29/2/2016','01/02'].forEach(function(s) {
console.log(s + ' : ' + isValidDate(s))
})
When testing a Date this way, only the month needs to be tested since if the date is out of range, the month will change. Same if the month is out of range. Any year is valid.
You can also test the bits of the date string:
function isValidDate2(s) {
var bits = s.split('/');
var y = bits[2],
m = bits[1],
d = bits[0];
// Assume not leap year by default (note zero index for Jan)
var daysInMonth = [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31];
// If evenly divisible by 4 and not evenly divisible by 100,
// or is evenly divisible by 400, then a leap year
if ((!(y % 4) && y % 100) || !(y % 400)) {
daysInMonth[1] = 29;
}
return !(/\D/.test(String(d))) && d > 0 && d <= daysInMonth[--m]
}
['0/10/2017','29/2/2016','01/02'].forEach(function(s) {
console.log(s + ' : ' + isValidDate2(s))
})

Does first function isValidDate(s) proposed by RobG will work for input string '1/2/'?
I think NOT, because the YEAR is not validated ;(
My proposition is to use improved version of this function:
//input in ISO format: yyyy-MM-dd
function DatePicker_IsValidDate(input) {
var bits = input.split('-');
var d = new Date(bits[0], bits[1] - 1, bits[2]);
return d.getFullYear() == bits[0] && (d.getMonth() + 1) == bits[1] && d.getDate() == Number(bits[2]);
}

I recommend to use moment.js. Only providing date to moment will validate it, no need to pass the dateFormat.
var date = moment("2016-10-19");
And then date.isValid() gives desired result.
Se post HERE

This solution does not address obvious date validations such as making sure date parts are integers or that date parts comply with obvious validation checks such as the day being greater than 0 and less than 32. This solution assumes that you already have all three date parts (year, month, day) and that each already passes obvious validations. Given these assumptions this method should work for simply checking if the date exists.
For example February 29, 2009 is not a real date but February 29, 2008 is. When you create a new Date object such as February 29, 2009 look what happens (Remember that months start at zero in JavaScript):
console.log(new Date(2009, 1, 29));
The above line outputs: Sun Mar 01 2009 00:00:00 GMT-0800 (PST)
Notice how the date simply gets rolled to the first day of the next month. Assuming you have the other, obvious validations in place, this information can be used to determine if a date is real with the following function (This function allows for non-zero based months for a more convenient input):
var isActualDate = function (month, day, year) {
var tempDate = new Date(year, --month, day);
return month === tempDate.getMonth();
};
This isn't a complete solution and doesn't take i18n into account but it could be made more robust.

var isDate_ = function(input) {
var status = false;
if (!input || input.length <= 0) {
status = false;
} else {
var result = new Date(input);
if (result == 'Invalid Date') {
status = false;
} else {
status = true;
}
}
return status;
}
this function returns bool value of whether the input given is a valid date or not. ex:
if(isDate_(var_date)) {
// statements if the date is valid
} else {
// statements if not valid
}

I just do a remake of RobG solution
var daysInMonth = [31,28,31,30,31,30,31,31,30,31,30,31];
var isLeap = new Date(theYear,1,29).getDate() == 29;
if (isLeap) {
daysInMonth[1] = 29;
}
return theDay <= daysInMonth[--theMonth]

This is ES6 (with let declaration).
function checkExistingDate(year, month, day){ // year, month and day should be numbers
// months are intended from 1 to 12
let months31 = [1,3,5,7,8,10,12]; // months with 31 days
let months30 = [4,6,9,11]; // months with 30 days
let months28 = [2]; // the only month with 28 days (29 if year isLeap)
let isLeap = ((year % 4 === 0) && (year % 100 !== 0)) || (year % 400 === 0);
let valid = (months31.indexOf(month)!==-1 && day <= 31) || (months30.indexOf(month)!==-1 && day <= 30) || (months28.indexOf(month)!==-1 && day <= 28) || (months28.indexOf(month)!==-1 && day <= 29 && isLeap);
return valid; // it returns true or false
}
In this case I've intended months from 1 to 12. If you prefer or use the 0-11 based model, you can just change the arrays with:
let months31 = [0,2,4,6,7,9,11];
let months30 = [3,5,8,10];
let months28 = [1];
If your date is in form dd/mm/yyyy than you can take off day, month and year function parameters, and do this to retrieve them:
let arrayWithDayMonthYear = myDateInString.split('/');
let year = parseInt(arrayWithDayMonthYear[2]);
let month = parseInt(arrayWithDayMonthYear[1]);
let day = parseInt(arrayWithDayMonthYear[0]);

My function returns true if is a valid date otherwise returns false :D
function isDate (day, month, year){
if(day == 0 ){
return false;
}
switch(month){
case 1: case 3: case 5: case 7: case 8: case 10: case 12:
if(day > 31)
return false;
return true;
case 2:
if (year % 4 == 0)
if(day > 29){
return false;
}
else{
return true;
}
if(day > 28){
return false;
}
return true;
case 4: case 6: case 9: case 11:
if(day > 30){
return false;
}
return true;
default:
return false;
}
}
console.log(isDate(30, 5, 2017));
console.log(isDate(29, 2, 2016));
console.log(isDate(29, 2, 2015));

It's unfortunate that it seems JavaScript has no simple way to validate a date string to these days. This is the simplest way I can think of to parse dates in the format "m/d/yyyy" in modern browsers (that's why it doesn't specify the radix to parseInt, since it should be 10 since ES5):
const dateValidationRegex = /^\d{1,2}\/\d{1,2}\/\d{4}$/;
function isValidDate(strDate) {
if (!dateValidationRegex.test(strDate)) return false;
const [m, d, y] = strDate.split('/').map(n => parseInt(n));
return m === new Date(y, m - 1, d).getMonth() + 1;
}
['10/30/2000abc', '10/30/2000', '1/1/1900', '02/30/2000', '1/1/1/4'].forEach(d => {
console.log(d, isValidDate(d));
});

Hi Please find the answer below.this is done by validating the date newly created
var year=2019;
var month=2;
var date=31;
var d = new Date(year, month - 1, date);
if (d.getFullYear() != year
|| d.getMonth() != (month - 1)
|| d.getDate() != date) {
alert("invalid date");
return false;
}

function isValidDate(year, month, day) {
var d = new Date(year, month - 1, day, 0, 0, 0, 0);
return (!isNaN(d) && (d.getDate() == day && d.getMonth() + 1 == month && d.getYear() == year));
}

Check for date overflow when date is in string format [duplicate]

I'm trying to test to make sure a date is valid in the sense that if someone enters 2/30/2011 then it should be wrong.
How can I do this with any date?

One simple way to validate a date string is to convert to a date object and test that, e.g.
// Expect input as d/m/y
function isValidDate(s) {
var bits = s.split('/');
var d = new Date(bits[2], bits[1] - 1, bits[0]);
return d && (d.getMonth() + 1) == bits[1];
}
['0/10/2017','29/2/2016','01/02'].forEach(function(s) {
console.log(s + ' : ' + isValidDate(s))
})
When testing a Date this way, only the month needs to be tested since if the date is out of range, the month will change. Same if the month is out of range. Any year is valid.
You can also test the bits of the date string:
function isValidDate2(s) {
var bits = s.split('/');
var y = bits[2],
m = bits[1],
d = bits[0];
// Assume not leap year by default (note zero index for Jan)
var daysInMonth = [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31];
// If evenly divisible by 4 and not evenly divisible by 100,
// or is evenly divisible by 400, then a leap year
if ((!(y % 4) && y % 100) || !(y % 400)) {
daysInMonth[1] = 29;
}
return !(/\D/.test(String(d))) && d > 0 && d <= daysInMonth[--m]
}
['0/10/2017','29/2/2016','01/02'].forEach(function(s) {
console.log(s + ' : ' + isValidDate2(s))
})

Does first function isValidDate(s) proposed by RobG will work for input string '1/2/'?
I think NOT, because the YEAR is not validated ;(
My proposition is to use improved version of this function:
//input in ISO format: yyyy-MM-dd
function DatePicker_IsValidDate(input) {
var bits = input.split('-');
var d = new Date(bits[0], bits[1] - 1, bits[2]);
return d.getFullYear() == bits[0] && (d.getMonth() + 1) == bits[1] && d.getDate() == Number(bits[2]);
}

I recommend to use moment.js. Only providing date to moment will validate it, no need to pass the dateFormat.
var date = moment("2016-10-19");
And then date.isValid() gives desired result.
Se post HERE

This solution does not address obvious date validations such as making sure date parts are integers or that date parts comply with obvious validation checks such as the day being greater than 0 and less than 32. This solution assumes that you already have all three date parts (year, month, day) and that each already passes obvious validations. Given these assumptions this method should work for simply checking if the date exists.
For example February 29, 2009 is not a real date but February 29, 2008 is. When you create a new Date object such as February 29, 2009 look what happens (Remember that months start at zero in JavaScript):
console.log(new Date(2009, 1, 29));
The above line outputs: Sun Mar 01 2009 00:00:00 GMT-0800 (PST)
Notice how the date simply gets rolled to the first day of the next month. Assuming you have the other, obvious validations in place, this information can be used to determine if a date is real with the following function (This function allows for non-zero based months for a more convenient input):
var isActualDate = function (month, day, year) {
var tempDate = new Date(year, --month, day);
return month === tempDate.getMonth();
};
This isn't a complete solution and doesn't take i18n into account but it could be made more robust.

var isDate_ = function(input) {
var status = false;
if (!input || input.length <= 0) {
status = false;
} else {
var result = new Date(input);
if (result == 'Invalid Date') {
status = false;
} else {
status = true;
}
}
return status;
}
this function returns bool value of whether the input given is a valid date or not. ex:
if(isDate_(var_date)) {
// statements if the date is valid
} else {
// statements if not valid
}

I just do a remake of RobG solution
var daysInMonth = [31,28,31,30,31,30,31,31,30,31,30,31];
var isLeap = new Date(theYear,1,29).getDate() == 29;
if (isLeap) {
daysInMonth[1] = 29;
}
return theDay <= daysInMonth[--theMonth]

This is ES6 (with let declaration).
function checkExistingDate(year, month, day){ // year, month and day should be numbers
// months are intended from 1 to 12
let months31 = [1,3,5,7,8,10,12]; // months with 31 days
let months30 = [4,6,9,11]; // months with 30 days
let months28 = [2]; // the only month with 28 days (29 if year isLeap)
let isLeap = ((year % 4 === 0) && (year % 100 !== 0)) || (year % 400 === 0);
let valid = (months31.indexOf(month)!==-1 && day <= 31) || (months30.indexOf(month)!==-1 && day <= 30) || (months28.indexOf(month)!==-1 && day <= 28) || (months28.indexOf(month)!==-1 && day <= 29 && isLeap);
return valid; // it returns true or false
}
In this case I've intended months from 1 to 12. If you prefer or use the 0-11 based model, you can just change the arrays with:
let months31 = [0,2,4,6,7,9,11];
let months30 = [3,5,8,10];
let months28 = [1];
If your date is in form dd/mm/yyyy than you can take off day, month and year function parameters, and do this to retrieve them:
let arrayWithDayMonthYear = myDateInString.split('/');
let year = parseInt(arrayWithDayMonthYear[2]);
let month = parseInt(arrayWithDayMonthYear[1]);
let day = parseInt(arrayWithDayMonthYear[0]);

My function returns true if is a valid date otherwise returns false :D
function isDate (day, month, year){
if(day == 0 ){
return false;
}
switch(month){
case 1: case 3: case 5: case 7: case 8: case 10: case 12:
if(day > 31)
return false;
return true;
case 2:
if (year % 4 == 0)
if(day > 29){
return false;
}
else{
return true;
}
if(day > 28){
return false;
}
return true;
case 4: case 6: case 9: case 11:
if(day > 30){
return false;
}
return true;
default:
return false;
}
}
console.log(isDate(30, 5, 2017));
console.log(isDate(29, 2, 2016));
console.log(isDate(29, 2, 2015));

It's unfortunate that it seems JavaScript has no simple way to validate a date string to these days. This is the simplest way I can think of to parse dates in the format "m/d/yyyy" in modern browsers (that's why it doesn't specify the radix to parseInt, since it should be 10 since ES5):
const dateValidationRegex = /^\d{1,2}\/\d{1,2}\/\d{4}$/;
function isValidDate(strDate) {
if (!dateValidationRegex.test(strDate)) return false;
const [m, d, y] = strDate.split('/').map(n => parseInt(n));
return m === new Date(y, m - 1, d).getMonth() + 1;
}
['10/30/2000abc', '10/30/2000', '1/1/1900', '02/30/2000', '1/1/1/4'].forEach(d => {
console.log(d, isValidDate(d));
});

Hi Please find the answer below.this is done by validating the date newly created
var year=2019;
var month=2;
var date=31;
var d = new Date(year, month - 1, date);
if (d.getFullYear() != year
|| d.getMonth() != (month - 1)
|| d.getDate() != date) {
alert("invalid date");
return false;
}

function isValidDate(year, month, day) {
var d = new Date(year, month - 1, day, 0, 0, 0, 0);
return (!isNaN(d) && (d.getDate() == day && d.getMonth() + 1 == month && d.getYear() == year));
}

JSP Date validation

I have an jsp page where the user selects two dates. I need to validate this date to ensure that the 1st date is not less than today's date. This is the script I am using:
var todaysDate = new Date();
if(document.frm.rentedOnDate.value < todaysDate )
{
alert("Rented date should not be before today");
document.frm.bank.focus();
return false;
}
if(document.frm.rentedOnDate.value> document.frm.returnDate.value )
{
alert("Return date should be after rented date");
document.frm.bank.focus();
return false;
}
These are the date selection fields:
<p>Select Rental Date: <input type="date" name="rentedOnDate"> </p>
<p>Select Return Date: <input type="date" name="returnDate"> </p>
The second script function works when the user enters a return date which is before the rented date but the first function does not work. Any ideas why?

Your second test is comparing strings, so I wouldn't count on it being perfectly reliable (a preceding zero could break it for instance).
You need to convert the strings (the .value fields) to proper date objects, and then compare them. This will resolve your first check, and improve your second check.
This function will parse a date provided in the "yyyy-mm-dd" fashion (optional 2-digit year yields 20xx). null is returned for an invalid date.
function getDate(str)
{
var dateParts = /^(\d\d(?:\d\d)?)-(\d\d?)-(\d\d?)$/.exec(str);
if (dateParts === null)
{
return null;
}
var year = parseInt(dateParts[1]);
if (year < 100)
{
year += 2000;
}
var month = parseInt(dateParts[2]) - 1;
var day = parseInt(dateParts[3]);
var result = new Date(year, month, day);
return year === result.getFullYear()
&& month === result.getMonth()
&& day === result.getDate() ? result : null;
}

function validateDate(dates){
re = /^(\d{1,2})\/(\d{1,2})\/(\d{4})$/;
var days=new Array(31,28,31,30,31,30,31,31,30,31,30,31);
if(regs = dates.match(re)) {
// day value between 1 and 31
if(regs[1] < 1 || regs[1] > 31) {
return false;
}
// month value between 1 and 12
if(regs[2] < 1 || regs[2] > 12) {
return false;
}
var maxday=days[regs[2]-1];
if(regs[2]==2){
if(regs[3]%4==0){
maxday=maxday+1;
}
}
if(regs[1]>maxday){
return false;
}
return true;
} else {
return false;
}
}

JavaScript Detecting Valid Dates

Possible Duplicate:
Detecting an “invalid date” Date instance in JavaScript
I was using the following to detect a valid date:
var text = $('#Date').val();
var date = Date.parse(text);
if (isNaN(date)) {
// Invalid date
}
But found that Date.parse thinks the following are valid dates (mm/dd/yyyy)
2/30/2011
11/31/2011
Any other way to detect invalid dates when the number of days surpasses the total number of
days in the month?
UPDATE: An even larger problem is that the jQuery validation plugin doesn't detect this as an invalid date either!
SOLUTION:
Based on #Guffa's comments I have created the following function to validate dates:
function validDate(text) {
var date = Date.parse(text);
if (isNaN(date)) {
return false;
}
var comp = text.split('/');
if (comp.length !== 3) {
return false;
}
var m = parseInt(comp[0], 10);
var d = parseInt(comp[1], 10);
var y = parseInt(comp[2], 10);
var date = new Date(y, m - 1, d);
return (date.getFullYear() == y && date.getMonth() + 1 == m && date.getDate() == d);
}

To check if a date is valid you can parse the components of the date, create a Date object from it, and check if the components in the data is the same as the parsed components. If you create a Date object from compnents that are out of range, the values will flow over to the next/previous period to create a valid date.
For example, new Date(2011,0,42) will create an object that contains the date 2/11/2011 instead of 1/42/2011.
By parsing the components instead of the full date you will also get around the problem with different date formats. My browser will for example expect a date format like y-m-d rather than d/m/y.
Example:
var text = '2/30/2011';
var comp = text.split('/');
var m = parseInt(comp[0], 10);
var d = parseInt(comp[1], 10);
var y = parseInt(comp[2], 10);
var date = new Date(y,m-1,d);
if (date.getFullYear() == y && date.getMonth() + 1 == m && date.getDate() == d) {
alert('Valid date');
} else {
alert('Invalid date');
}
Demo: http://jsfiddle.net/Guffa/UeQAK/

If your date format is fixed as M/D/YYYY, you could re-format the parsed date and see if it matches the input:
var d = new Date(Date.parse(str))
return str === (d.getMonth()+1)+'/'+d.getDate()+'/'+d.getYear();
However, that won't tolerate whitespace or zero-padded numbers.
If you don't need to keep the user's input exactly, you could just reformat the date anyway and pretend that was what they typed.
But if you can't do that either, I'd parse out the components myself using a RegExp and then compare them to values from the Date methods.

You could write a script to do this manually:
function checkDate(day, month) {
if ((month == 4 || month == 6 || month == 9 || month == 11) && day < 30) {
alert("Date is valid")
}
else if (month == 2 && day <= 28) {
alert("Date is valid")
}
else if ((month == 1 || month == 3 || month == 5 || month == 7 || month == 8 || month == 10 || month == 12) && day <= 31) {
alert("Date is valid")
}
else {
alert("Date is in-valid")
}
}
Of course, you would also need something to look out for leap years, but just remember that any year divisible by 4 and not by 100 is a leap year unless the first two digits of the year are divisible by 4. That should be easy to include in this function.

The example is wrong
the correct is
if ((month == 4 || month == 6 || month == 9 || month == 11) && day <= 30)
<= instead of =
But the example are great!

A simple, intrinsic way to achieve this can be:
let dateObj = document.getElementById('Date');
if (dateObj.validity.badInput) {
// show error message
}
Now some date formatting can be done, but HTML date-picker event has properties like badInput and valid to check invalid dates.

validate javascript date

Is there a fast way to validate that a date/time in this format is valid?
I would prefer not to breaking it down with substrings and rebuilding it if possible
"YYYY-MM-DD HH:MM:SS"

You could parse the date string as an ISO string (by converting the space to a "T" and appending the Zulu timezone, e.g. "2011-08-16T12:34:56Z") then compare the resulting date's ISO string to the original ISO string.
function isValidDateString(s) {
try {
var isoStr = (""+s).replace(/ /,'T') + "Z"
, newStr = new Date(isoStr).toISOString();
return isoStr.slice(0,19) == newStr.slice(0,19);
} catch (e) {
return false;
}
}
This way, if the date string has invalid format, then the string "Invalid Date" will not equal the original and if it were to roll (e.g. if the day was invalid for the month) then the string value of the parsed date will not equal the original string.
[Edit]
Note the changes to the example code required by the timezone fix.

Try a regular expression like this.
Edit: Here is the string you'll want to match against:
^([1-3][0-9]{3,3})-(0?[1-9]|1[0-2])-(0?[1-9]|[1-2][1-9]|3[0-1])\s([0-1][0-9]|2[0-4]):([0-5][0-9]):([0-5][0-9])$

You can use this regex.
/^([0-9]{4})-([0-1][0-9])-([0-3][0-9])\s([0-1][0-9]|[2][0-3]):([0-5][0-9]):([0-5][0-9])$/.test("2007-08-04 18:01:01"); //true
/^([0-9]{4})-([0-1][0-9])-([0-3][0-9])\s([0-1][0-9]|[2][0-3]):([0-5][0-9]):([0-5][0-9])$/.test("2007-08-04 18:01:0"); //false

The following code below will check to see if the date input is actually a valid date.
At first glance it looks big, but it's mostly the comments.
It requires no substrings and no regular expression.
The way JavaScript works is that, if you break down a Date object with an invalid date (04/32/2010) to it's total milliseconds and then create another Date object with those milliseconds, it will not create a Date object that displays the incorrect date (04/32/2010) it will compensate and create the proper Date (05/01/2010).
So simply, if the input is different than the new Date object, then the date is not valid.
http://jsfiddle.net/dceast/vmHjN/ - Here is an example of it on JSFiddle.
var compareDate, checkDates = false;
var validateObject = {
init: function(year, month, day) {
return this.compareDate.init(year, month, day);
},
compareDate: {
init: function(year, month, day) {
var isValid = false;
// Compensate for zero based index, if month was not
// subtracted from one 0 === Jan, 1 === Feb, 2 === Mar
month -= 1;
// Create a new date object with the selected
// year, month, and day values and retrieve the
// milliseconds from it.
var mSeconds = (new Date(year, month, day)).getTime();
var objDate = new Date();
// Set the time of the object to the milliseconds
// retrieved from the original date. This will
// convert it to a valid date.
objDate.setTime(mSeconds);
// Compare if the date has changed, if it has then
// the date is not valid
if (objDate.getFullYear() === year &&
objDate.getMonth() === month &&
objDate.getDate() === day)
{
isValid = true;
}
return isValid;
}
}
};

I did so and it worked
<html>
<head>
<title>valida data</title>
<script>
function valData(data){//dd/mm/aaaa
day = data.substring(0,2);
month = data.substring(3,5);
year = data.substring(6,10);
if( (month==01) || (month==03) || (month==05) || (month==07) || (month==08) || (month==10) || (month==12) ) {//months 31 days
if( (day < 01) || (day > 31) ){
alert('invalid date');
}
} else
if( (month==04) || (month==06) || (month==09) || (month==11) ){//months 30 days
if( (day < 01) || (day > 30) ){
alert('invalid date');
}
} else
if( (month==02) ){//February and leap year
if( (year % 4 == 0) && ( (year % 100 != 0) || (year % 400 == 0) ) ){
if( (day < 01) || (day > 29) ){
alert('invalid date');
}
} else {
if( (day < 01) || (day > 28) ){
alert('invalid date');
}
}
}
}
</script>
</head>
<body>
<form>
<input type="text" name="data" id="data" onBlur="return valData(this.value)" />
</form>
</body>
</html>