System identifier
Encyclopedia
A system identifier is a document processing construct introduced in the HyTime
markup language as a supplement to SGML. It was subsequently incorporated into the HTML
and XML
markup language
s.
In HyTime, there are two kinds of system identifier: formal system identifier (FSI) and simple system identifier.
In HTML and XML, a system identifier is a fragmentless URI reference
. It typically occurs in a Document Type Declaration
. In this context, it is intended to identify a document type which is used exclusively in one application, whereas a public identifier
is meant to identify a document type that may span more than one application.
In the following example, the system identifier is the text contained within quotes:
HyTime
HyTime is a markup language that is an "application" of SGML. HyTime defines a set of hypertext-oriented element types that, in effect, supplement SGML and allow SGML document authors to build hypertext and multimedia presentations in a standardized way.HyTime is an international standard...
markup language as a supplement to SGML. It was subsequently incorporated into the HTML
HTML
HyperText Markup Language is the predominant markup language for web pages. HTML elements are the basic building-blocks of webpages....
and XML
XML
Extensible Markup Language is a set of rules for encoding documents in machine-readable form. It is defined in the XML 1.0 Specification produced by the W3C, and several other related specifications, all gratis open standards....
markup language
Markup language
A markup language is a modern system for annotating a text in a way that is syntactically distinguishable from that text. The idea and terminology evolved from the "marking up" of manuscripts, i.e. the revision instructions by editors, traditionally written with a blue pencil on authors' manuscripts...
s.
In HyTime, there are two kinds of system identifier: formal system identifier (FSI) and simple system identifier.
In HTML and XML, a system identifier is a fragmentless URI reference
Uniform Resource Identifier
In computing, a uniform resource identifier is a string of characters used to identify a name or a resource on the Internet. Such identification enables interaction with representations of the resource over a network using specific protocols...
. It typically occurs in a Document Type Declaration
Document Type Declaration
A Document Type Declaration, or DOCTYPE, is an instruction that associates a particular SGML or XML document with a Document Type Definition...
. In this context, it is intended to identify a document type which is used exclusively in one application, whereas a public identifier
Public identifier
A public identifier is a document processing construct in SGML and XML.In HTML and XML, a public identifier is meant to be universally unique within its application scope. It typically occurs in a Document Type Declaration....
is meant to identify a document type that may span more than one application.
In the following example, the system identifier is the text contained within quotes:
<!DOCTYPE html SYSTEM "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd ">