While the tips are carefully reviewed by the participants of the group, they should not be seen as anything else than informative bits of wisdom, and especially, they are not normative W3C technical specifications.

dating system which-9

More information on calendars and their histories can be found in E. Richards' "Calendars" chapter of the Explanatory Supplement to The Astronomical Almanac (ed. For more information on the API, please see the documentation page.

There are so many formats available, most of them incompatible with others, that it can be a usability nightmare to choose a date representation when writing for an international, cross-cultural audience, as is the case on the web.

Fortunately, there is one solution in the ISO-developed international date format.

The worst potential usability problems come when the date is written only with numbers as in the following example, because the date's interpretation will be different from one country to another. Note that this format can also be used to represent precise date and time, with timezone information Using numerical dates does have also some pitfalls with regard to readability and usability, as explained in the Date formats The W3C QA Tips are short documents explaining useful bits of knowledge for Web developers or designers, hosted and produced by the Quality Assurance Interest Group at W3C.

Julian dates (abbreviated JD) are simply a continuous count of days and fractions since noon Universal Time on January 1, 4713 BC (on the Julian calendar).

Almost 2.5 million days have transpired since this date.As used here, the two calendars have identical month names and number of days in each month, and differ only in the rule for leap years.The Julian calendar has a leap year every fourth year, while the Gregorian calendar has a leap year every fourth year except century years not exactly divisible by 400.The drawing of the computer was supposedly based on the huge SSEC (Selective Sequence Electronic Calculator) mainframe that IBM had shown off in its Madison Avenue showroom in New York City from 1948-1952.But the reason that it was making an appearance on the cover of the New Yorker almost a decade later had less to do with the specific computer in question, and more to do with what computer technology was coming to represent by the early 1960s: a potential challenge to the capacities and talents of human beings. By the early 1960s, mainframes had crept into the popular consciousness through news reports and advertising.Thus, there is a ten-day gap in calendar dates, but no discontinuity in Julian dates or days of the week: 4 October 1582 (Julian) is a Thursday, which begins at JD 2299159.5; and 15 October 1582 (Gregorian) is a Friday, which begins at JD 2299160.5.