5. Dates

ISO 8601 defines date and time formats. Some benefits include:

• language-independent and unambiguous world-wide
• sortable with a trivial string comparison
• easily readable and writable by software
• compatible with standards ISO 9075 and rfc 3339
• The ISO Extended format for common date is YYYY-MM-DD, and for time is hh:mm:ss.

For an event with an offset from UTC, use YYYY-MM-DDThh:mm:ss±hh:mm.

Never use a local date/time format for a non-local event. Instead, use UTC, as in YYYY-MM-DDThh:mm:ssZ (Z is the only letter suffix).

The T can be omitted where that would not cause ambiguity. For rfc 3339 compliance, it may be replaced by a space and for SQL, it must be replaced by a single space.

Year 0000 is unrecognized by some formats (XML Schema, xs:date).

• ECMA-262 Date.prototype, s. 15.9
• A summary of the international standard date and time notation, by Markus Kuhn
• http://en.wikipedia.org/wiki/ISO_8601
• ISO 8601:2004(E)
• W3C QA Tip: Use international date format (ISO)
• RFC 3339, Date and Time on the Internet: Timestamps
• http://www.w3.org/TR/xmlschema-2/#dateTime

• 5.1 How do I format a Date object with javascript?
• 5.2 How can I create a Date object from a String?

Other FAQ Resources:

• The Table of Contents
• A Single-page version of the FAQ
• More in-depth articles on selected topics