A calendar date is a reference to a particular day represented within a calendar system. The calendar date allows the specific day to be identified. The number of days between two dates may be calculated. For example, "25 December 2024" is ten days after "15 December 2024". The date of a particular event depends on the observed time zone. For example, the air attack on Pearl Harbor that began at 7:48 a.m. Hawaiian time on 7 December 1941 took place at 3:18 a.m. Japan Standard Time, 8 December in Japan.
Hypertext Markup Language (HTML) is the standard markup language for documents designed to be displayed in a web browser. It defines the content and structure of web content. It is often assisted by technologies such as Cascading Style Sheets (CSS) and scripting languages such as JavaScript, a programming language.
ISO 8601 is an international standard covering the worldwide exchange and communication of date and time-related data. It is maintained by the International Organization for Standardization (ISO) and was first published in 1988, with updates in 1991, 2000, 2004, and 2019, and an amendment in 2022. The standard provides a well-defined, unambiguous method of representing calendar dates and times in worldwide communications, especially to avoid misinterpreting numeric dates and times when such data is transferred between countries with different conventions for writing numeric dates and times.
An open standard is a standard that is openly accessible and usable by anyone. It is also a common prerequisite that open standards use an open license that provides for extensibility. Typically, anybody can participate in their development due to their inherently open nature. There is no single definition, and interpretations vary with usage. Examples of open standards include the GSM, 4G, and 5G standards that allow most modern mobile phones to work world-wide.
The modern 24-hour clock is the convention of timekeeping in which the day runs from midnight to midnight and is divided into 24 hours. This is indicated by the hours passed since midnight, from 00(:00) to 23(:59), with 24(:00) as an option to indicate the end of the day. This system, as opposed to the 12-hour clock, is the most commonly used time notation in the world today, and is used by the international standard ISO 8601.
Web standards are the formal, non-proprietary standards and other technical specifications that define and describe aspects of the World Wide Web. In recent years, the term has been more frequently associated with the trend of endorsing a set of standardized best practices for building web sites, and a philosophy of web design and development that includes those methods.
A timestamp is a sequence of characters or encoded information identifying when a certain event occurred, usually giving date and time of day, sometimes accurate to a small fraction of a second. Timestamps do not have to be based on some absolute notion of time, however. They can have any epoch, can be relative to any arbitrary time, such as the power-on time of a system, or to some arbitrary time in the past.
A year zero does not exist in the Anno Domini (AD) calendar year system commonly used to number years in the Gregorian calendar ; in this system, the year 1 BC is followed directly by year AD 1. However, there is a year zero in both the astronomical year numbering system, and the ISO 8601:2004 system, a data interchange standard for certain time and calendar information. There is also a year zero in most Buddhist and Hindu calendars.
Different conventions exist around the world for date and time representation, both written and spoken.
An IETF BCP 47 language tag is a standardized code that is used to identify human languages on the Internet. The tag structure has been standardized by the Internet Engineering Task Force (IETF) in Best Current Practice (BCP) 47; the subtags are maintained by the IANA Language Subtag Registry.
ISO 2014 is an international standard that was issued in April 1976, and superseded by ISO 8601 in June 1988. ISO 2014 was the standard that originally introduced the all-numeric date notation [YYYY]-[MM]-[DD] with the digits in order starting with the most significant digit first. It was technically identical to ISO Recommendation R 2014 from 1971.
A Formal Public Identifier (FPI) is a short piece of text with a particular structure that may be used to uniquely identify a product, specification or document. FPIs were introduced as part of Standard Generalized Markup Language (SGML), and serve particular purposes in formats historically derived from SGML. Some of their most common uses are as part of document type declarations (DOCTYPEs) and document type definitions (DTDs) in SGML, XML and historically HTML, but they are also used in the vCard and iCalendar file formats to identify the software product which generated the file.
Date and time notation in the United States differs from that used in nearly all other countries. It is inherited from one historical branch of conventions from the United Kingdom. American styles of notation have also influenced customs of date notation in Canada, creating confusion in international commerce.
In Poland, the official system for representing dates and times follows the international ISO 8601 standard. However, in less official use, other conventions prevail, such as the day-month-year order and several Polish language abbreviations.
Date and time notation in Sweden mostly follows the ISO 8601 standard: dates are generally written in the form YYYY-MM-DD. Although this format may be abbreviated in a number of ways, almost all Swedish date notations state the month between the year and the day. Months are not capitalised when written. The week number may also be used in writing and in speech. Times are generally written using 24-hour clock notation, with full stops as separators, although 12-hour clock notation is more frequently used in speech.
Date and time notation in the United Kingdom records the date using the day–month–year format. The time can be written using either the 24-hour clock (23:59) or the 12-hour clock (11:59 p.m.), either with a colon or a full stop (11.59 p.m.).
The European Committee for Standardization (CEN) and (CENELEC) adopted ISO 8601 with EN 28601, now EN ISO 8601. As a European Norm, CEN and CENELEC member states are obligated to adopt the standard as national standard without alterations as well.
ISO 8601 has been adopted as BIS IS 7900:2001.
Date and time notation in the Philippines varies across the country in various, customary formats. Some government agencies in the Philippines have adopted time and date representation standard based on the ISO 8601, notably the Philippines driver's license and the Unified Multi-Purpose ID.
Date and time notation in Pakistan is based on the Gregorian and Islamic calendars. Pakistan has not officially adopted any time and date representation standard based on the ISO 8601.
