Home/ Questions/Q 8959259
In Process

The Archive Base Latest Questions

Editorial Team
  • 0
Asked: 2026-06-15T15:23:41+00:00

After reading this question – which also provides links to documentation , I still

  • 0

After reading this question – which also provides links to documentation , I still have a question about the documentation.

MDN : Date.parse

A string representing an RFC2822 or ISO 8601 date.

Ok , RFC2282 :

date-time       =       [ day-of-week "," ] date FWS time [CFWS]
day-of-week     =       ([FWS] day-name) / obs-day-of-week
day-name        =       "Mon" / "Tue" / "Wed" / "Thu" /
                       "Fri" / "Sat" / "Sun"

date            =       day month year
year            =       4*DIGIT / obs-year
month           =       (FWS month-name FWS) / obs-month
month-name      =       "Jan" / "Feb" / "Mar" / "Apr" /
                        "May" / "Jun" / "Jul" / "Aug" /
                        "Sep" / "Oct" / "Nov" / "Dec"

day             =       ([FWS] 1*2DIGIT) / obs-day

Now – ISO8601

 Year:
      YYYY (eg 1997)
   Year and month:
      YYYY-MM (eg 1997-07)
   Complete date:
      YYYY-MM-DD (eg 1997-07-16)

Ok.

Questions :

  • MDN provided a pattern sample (which is working) "Dec 25, 1995" which is not found in 2282 nor in ISO .
    How come this sample works ? the order must be day month year ( according to 2282) .

  • the separators in the standards are [space] ( in 2282) and [-] in ISO.

    So why this sample works ( cross browser) ? Date.parse("2011/11/23")

Share

Leave an answer

You must login to add an answer.

Need An Account,

1 Answer

  1. Editorial Team

    For Date.parse, have a look at the EcmaScript specification, section 15.9.4.2:

    The String may be interpreted as a local time, a UTC time, or a time
    in some other time zone, depending on the contents of the String. The
    function first attempts to parse the format of the String according to
    the rules called out in Date Time String Format (15.9.1.15). If the
    String does not conform to that format the function may fall back to
    any implementation-specific heuristics or implementation-specific date
    formats    . Unrecognizable Strings or dates containing illegal element
    values in the format String shall cause Date.parse to return NaN.

    So, MDN’s Mozilla-specific documentation is quite near that. The official “EcmaScript Date Time String Format” is a subset of ISO 8601, otherwise Gecko browsers try to interpret it as RFC 2822 or even something else (this might include "Dec 25, 1995"). I strongly suspect that "2011/11/23" really works cross-browser, although it might be true for recent versions.

    • 0