JavaScript's getDate returns wrong date

Question

The following script returns 20 instead of 21!

var d = new Date("2010/03/21");
document.write(d.getDate());

What am I doing wrong? Is this a JavaScript bug?

Answer 1

I tested this code in Firefox 3.6 and IE 8:

<script type="text/javascript">

var d = new Date("2010/03/21");
document.write(d.getDate());

</script> 

It's showing the right date: 21

For more information, look at: JavaScript Date Object

You can also read about JavaScript Compatibility considerations at Wikipedia.

Answer 2

I wrote the following code in my browser's address bar and the result was 21

javascript:alert(new Date("2010/03/21").getDate())

There is no such thing as a Javascript bug, since there is many Javascript implementations, so you'll want to refer to a specific implementation.

The implementation I tested was Chrome 4.1.249. What's yours?

Answer 3

The Date.parse method is implementation dependent (new Date(string) is equivalent to Date.parse(string)).

While this format will be available on modern browsers, you cannot be 100% sure that the browser will interpret exactly your desired format.

I would recommend you to manipulate your string, and use the Date constructor with the year, month and day arguments:

// parse a date in yyyy-mm-dd format
function parseDate(input) {
  var parts = input.match(/(\d+)/g);
  // new Date(year, month [, date [, hours[, minutes[, seconds[, ms]]]]])
  return new Date(parts[0], parts[1]-1, parts[2]); // months are 0-based
}

Answer 4

Any chance it's treating the string argument as UTC and the resulting Date object as local time, or vice versa? That could throw it off. Compare d.getDate() to d.getUTCDate().

Answer 5

http://jsbin.com/aqoki3/edit - here with code you posted I get 21. So its not JS bug. Maybe its bug in your browser implementation (of JS).
So to correctly init your date var use new Date(year, month, date [, hour, minute, second, millisecond ]) (https://developer.mozilla.org/en/Core_JavaScript_1.5_Reference/Objects/Date). This way you will be sure that day is 21 becouse you implicitly set it to 21.

Answer 6

You cant't create Date object by passing string argument shows like date.

Create Like this way.

var str_date = "2010/03/21"; var date = new Date();

var date_elements = str_date.split("/");

date.setYear(date_elements[0]); date.setMonth(date_elements[1]); date.setDay(date_elements[2]);

alert(date.toString);

give attention on date.toString method. it returns full date String. date.getDate will only give you day of that day.

for more info of Date object, refer www.w3school.com

Answer 7

I get the same date (21) in firfox,safari,chrome,opera and IE, whether I use the string "2010/03/21" or the integer date arguments (2010,2,21).

I am using a windows machine and new versions of the browsers-

you can test to see if your client parses a different date from the string, which is the only place I see for a problem.

if(new Date("2010/03/21")- new Date(2010,2,21)){
alert(new Date("2010/03/21"));
}