Why does this Javascript work in FF3.6? new Date("2010-06-09T19:20:30+01:00");

Question

Here's the sample code:

var d = new Date("2010-06-09T19:20:30+01:00");
document.write(d);

On FF3.6 this will give you:

Wed Jun 09 2010 14:20:30 GMT-0400 (EST)

Other browers tested; Chrome 5, Safari 4, IE7 give:

Invalid Date

I know there is limited to no support for ISO8601 dates, but does anyone know what and/or where the difference is in FF3.6 that allows this to work?

My thought is that FF is just stripping out what it doesn't understand while the others are not.

Has anyone else seen this and/or getting different results from the test script?

Answer 1

ISO 8601 is often used to pass time/date info between systems

It allows yyyy-mm-dd alone for midnight GMT of that date,

or the date followed by 'T' and time data,

with optional seconds and milliseconds (after ',').

yyyy-mm-ddThh:mm

yyyy-mm-ddThh:mm:ss.xxx

You finish with either Z for greenwich time, nothing, also for Greenwich time, or a + or - and the hh:mm offset from GMT.

You can make your own method- this passes back the local Date, using the built in method if it is available- only firefox, so far.

Date.ISO= function(s){
    var D= new Date(s);
    if(D.getDate()) return D;

    var M= [], min= 0,
    Rx=  /([\d:]+)(\.\d+)?(Z|(([+\-])(\d\d):(\d\d))?)?$/;
    D= s.substring(0, 10).split("-");

    if(s.length> 11){
        M= s.substring(11).match(Rx) || [];
        if(M[1]) D= D.concat(M[1].split(":"));
        if(M[2]) D.push(Math.round(M[2]*1000));
    }
    D= D.map(function(itm){return parseInt(itm, 10);});
    D[1]-= 1;
    while(D.length < 7) D.push(0);
    if(M[4]){
        min= parseInt(M[6])*60 + parseInt(M[7], 10);
        if(M[5]== "+") min*= -1;
    }
    D= new Date(Date.UTC.apply(Date, D));
    if(!D.getDate()) throw "Bad Date- " + s;

    if(min) D.setMinutes(D.getMinutes()+ min);
    return D;
}

//tests

var s= "2010-06-09T19:20:30+01:00";
alert(Date.ISO(s).toUTCString());

/* value: (String) Safari 5.0: Wed, 09 Jun 2010 18:20:30 GMT

MSIE 8.0: Wed, 9 Jun 2010 18:20:30 UTC

Chrome 5.0.375.70: Wed, 09 Jun 2010 18:20:30 GMT

Opera 10.53: Wed, 09 Jun 2010 18:20:30 GMT

Firefox 3.6.3: Wed, 09 Jun 2010 18:20:30 GMT */

Note- To work in IE (and older browsers) you'll need to fake the array map method-

if(![].map){
    Array.prototype.map= function(fun, scope){
        var L= this.length, A= Array(this.length), i= 0, val;
        if(typeof fun== 'function'){
            while(i< L){
                if(i in this){
                    A[i]= fun.call(scope, this[i], i, this);
                }
                ++i;
            }
            return A;
        }
    }
}