What result is right for the following test cases?

                                                    //Chrome 19     Opera 12       Firefox 11    IE 9          Safari 5.1.1
console.log(Date.parse("2012-11-31T23:59:59.000Z"));//1354406399000 NaN            NaN           1354406399000 NaN
console.log(Date.parse("2012-12-31T23:59:59.000Z"));//1356998399000 1356998399000  1356998399000 1356998399000 1356998399000
console.log(Date.parse("2012-12-31T23:59:60.000Z"));//NaN           NaN            NaN           NaN           1356998400000
console.log(Date.parse("2012-04-04T05:02:02.170Z"));//1333515722170 1333515722170  1333515722170 1333515722170 1333515722170
console.log(Date.parse("2012-04-04T24:00:00.000Z"));//NaN           1333584000000  1333584000000 1333584000000 1333584000000
console.log(Date.parse("2012-04-04T24:00:00.500Z"));//NaN           NaN            1333584000500 1333584000500 NaN
console.log(Date.parse("2012-12-31T10:08:60.000Z"));//NaN           NaN            NaN           NaN           1356948540000
console.log(Date.parse("2012-13-01T12:00:00.000Z"));//NaN           NaN            NaN           NaN           NaN
console.log(Date.parse("2012-12-32T12:00:00.000Z"));//NaN           NaN            NaN           NaN           NaN
console.log(Date.parse("2012-12-31T25:00:00.000Z"));//NaN           NaN            NaN           NaN           NaN
console.log(Date.parse("2012-12-31T24:01:00.000Z"));//NaN           NaN            NaN           1356998460000 NaN
console.log(Date.parse("2012-12-31T12:60:00.000Z"));//NaN           NaN            NaN           NaN           NaN
console.log(Date.parse("2012-12-31T12:00:60.000Z"));//NaN           NaN            NaN           NaN           1356955260000
console.log(Date.parse("2012-00-31T23:59:59.000Z"));//NaN           NaN            NaN           NaN           NaN
console.log(Date.parse("2012-12-00T23:59:59.000Z"));//NaN           NaN            NaN           NaN           NaN
console.log(Date.parse("2012-02-29T12:00:00.000Z"));//1330516800000 1330516800000  1330516800000 1330516800000 1330516800000
console.log(Date.parse("2011-02-29T12:00:00.000Z"));//1298980800000 NaN            NaN           1298980800000 NaN
console.log(Date.parse("2011-03-01T12:00:00.000Z"));//1298980800000 1298980800000  1298980800000 1298980800000 1298980800000

// extended years:
console.log(Date.parse("0000-01-01T00:00:00.000Z"));//-621672192e5  -621672192e5   -621672192e5  -621672192e5  -621672192e5
console.log(Date.parse("+275760-09-13T00:00:00.000Z"));//8.64e15    NaN            8.64e15       8.64e15       8.64e15
console.log(Date.parse("-271821-04-20T00:00:00.000Z"));//-8.64e15   NaN            -8.64e15      -8.64e15      -8.6400000864e15
console.log(Date.parse("+275760-09-13T00:00:00.001Z"));//NaN        NaN            NaN           8.64e15 + 1   8.64e15 + 1
console.log(Date.parse("-271821-04-19T23:59:59.999Z"));//NaN        NaN            NaN           -8.64e15 - 1  -8.6400000864e15 - 1

// https://github.com/kriskowal/es5-shim/issues/80 Safari bug with leap day
console.log(Date.parse("2034-03-01T00:00:00.000Z") -
            Date.parse("2034-02-27T23:59:59.999Z"));//86400001      86400001       86400001       86400001      1

// Time Zone Offset
console.log(Date.parse("2012-01-29T12:00:00.000+01:00"));//132783480e4 132783480e4  132783480e4  132783480e4    132783480e4
console.log(Date.parse("2012-01-29T12:00:00.000-00:00"));//132783840e4 132783840e4  132783840e4  132783840e4    132783840e4
console.log(Date.parse("2012-01-29T12:00:00.000+00:00"));//132783840e4 132783840e4  132783840e4  132783840e4    132783840e4
console.log(Date.parse("2012-01-29T12:00:00.000+23:59"));//132775206e4 132775206e4  132775206e4  132775206e4    132775206e4
console.log(Date.parse("2012-01-29T12:00:00.000-23:59"));//132792474e4 132792474e4  132792474e4  132792474e4    132792474e4
console.log(Date.parse("2012-01-29T12:00:00.000+24:00"));//NaN         1327752e6    NaN          1327752000000  1327752000000
console.log(Date.parse("2012-01-29T12:00:00.000+24:01"));//NaN         NaN          NaN          1327751940000  1327751940000
console.log(Date.parse("2012-01-29T12:00:00.000+24:59"));//NaN         NaN          NaN          1327748460000  1327748460000
console.log(Date.parse("2012-01-29T12:00:00.000+25:00"));//NaN         NaN          NaN          NaN            NaN
console.log(Date.parse("2012-01-29T12:00:00.000+00:60"));//NaN         NaN          NaN          NaN            NaN
console.log(Date.parse("-271821-04-20T00:00:00.000+00:01"));//NaN      NaN          NaN          -864000000006e4 -864000008646e4
console.log(Date.parse("-271821-04-20T00:01:00.000+00:01"));//-8.64e15 NaN          -8.64e15     -8.64e15        -864000008640e4

Seems that ECMAScript should be more specific for edge cases; currently is says that invalid date formats are implementation dependent, am I right?

• javascript
• datetime
• iso
• ecmascript-5
• iso8601

According to the ES5 spec, Date.parse will only work with valid ISO 8601 dates. Anything else is implementation dependent (in practice, IE < 9 doesn't work with standard ISO dates, it requires a '/' seperator). So if you feed it an invalid date (such as 2012-11-31) you can get anythying, from 2012-12-01 to an error.

In your tests:

2012-12-31T23:59:60.000Z

should work, though probably not as you expect. Using 60 for seconds indicates a leap second, it isn't equivalent to 24:00:00, only Safari seems to get that right.

Also:

2012-04-04T24:00:00.000Z

should work, it indicates midnight at the end of 4 April, 2012 so Firefox is in error there.

The formats that ES5 implementations should support are in the spec.

Oh, and you should probably also test omission of the 'T' (since it is optional in certain cases that I think include browsers) and different time zones such as:

2012-04-03 23:50:00+10:00
2012-04-03 23:50:00-04:15
2012-04-03 23:50:00+10
20120403T235000+1000

and so on with YYYYDDD and YYYYWwwD formats, though implementations aren't required to support them.