Date.UTC difference

[dotnetCarpenter]

While testing my brand new Ext app, I noticed something odd.
In Firefox Date.UTC is zero based but 1-based in IE. It throws my hole application but I can easy remedy that by using


if(Ext.IE){
// use 1-based UTC
} else {
// use 0-based UTC
}

I googled IE and Date.UTC but apparently this difference is not documented (anywhere I looked)! I'm thinking that maybe UTC is not as error resilient that I thought. What does the DateField use?

[mystix]

:-/ what test case did you use?

[dotnetCarpenter]

document.write(new Date(Date.UTC(2007, 0, 0));

Will display Mon Jan 1 00:00:00 UTC+0100 2007 in FF
and Sun Dec 31 01:00:00 UTC+0100 2006 in IE (in my timezone).I find that using Ext.parseDate will normalize the date creation between browsers.

[mystix]

hmmm... i think you've misunderstood...

it's incorrect to say IE's js Date object is 0-based.

the javascript Date object's Date.UTC() method accepts 1-based day arguments -- this happens regardless of browser flavour (see http://developer.mozilla.org/en/docs/Core_JavaScript_1.5_Reference:Objects:Date:UTC)

IE's js Date object, in this case, makes a good attempt at being smart when an integer day argument less than 1 is passed to the Date.UTC() method -- it starts at the 1st day of the given month and counts backwards.

try the following code


// returns the same millisecond value in FF / IE
Date.UTC(2007, 0, 1);

// in FF, returns the same millisecond value as above; in IE, returns the millisecond value for Dec 31, 2006
Date.UTC(2007, 0, 0);

// in FF, returns the same millisecond value as above; in IE, returns the millisecond value for Dec 30, 2006
Date.UTC(2007, 0, -1);

[dotnetCarpenter]

it's incorrect to say IE's js Date object is 0-based.

Yes, I said that IE Date.UTC method is 1-based.

If I read the docs correctly the first day of 2007 would be Date.UTC(2007, 0, 1).

Parameters

year
A year after 1900.

month
An integer between 0 and 11 representing the month.

date
An integer between 1 and 31 representing the day of the month.

[dotnetCarpenter]

Thanks for the link

[mystix]

Yes, I said that IE Date.UTC method is 1-based.

my bad. :">

meant to say "FF", but ended up typing "IE".
anyway, here's one more link i was reading:
http://www.merlyn.demon.co.uk/js-date5.htm#SLGD

knock yourself out ;)

[dotnetCarpenter]

puh that's too much! :))