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Information about Fragment Identifier

In computer hypertext, a fragment identifier is a short string of characters that refers to a resource that is subordinate to another, primary resource. The primary resource is identified by a Uniform Resource Identifier (URI), and the fragment identifier points to the subordinate resource. Typically, the fragment identifier is appended to the Uniform Resource Locator (URL —a type of URI) for a hypertext document and is meant to identify a portion of that document.

A fragment identifier is defined by RFC 3986 as an optional component of a URI reference, and it must conform to a certain syntax. The syntax requires that the fragment identifier be separated from the rest of the URI reference by a # (number sign) character. The separator is not considered part of the fragment identifier.

Examples

  • In HTML applications, http://example.org/schmoo.html#tag1 will refer to the element containing the "anchor" attribute name="tag1" in the document named "http://example.org/schmoo.html". It does not matter if the document is actually accessible at that location on the Internet.
  • In XML applications, http://example.org/schmoo.xml#xpointer(//Rube) should employ an XPointer, returning all XML elements named "Rube" from the document named "http://example.org/schmoo.xml". It does not matter if the document is actually accessible at that location on the Internet.
  • In RDF vocabularies, such as RDFS, OWL, or SKOS, fragment identifiers are used to identify resources in the same XML Namespace, but are not necessarily corresponding to a specific part of a document. For example http://www.w3.org/2004/02/skos/core#broader identifies the concept "broader" in SKOS Core vocabulary, but it does not refer to a specific part of the resource identified by http://www.w3.org/2004/02/skos/core, a complete RDF file in which semantics of this specific concept is declared, along with other concepts in the same vocabulary.

Processing

The fragment identifier functions differently than the rest of the URI: namely, its processing is exclusively client-side with no participation from the server. When an agent (such as a Web browser) requests a resource from a Web server, the agent sends the URI to the server, but does not send the fragment. Instead, the agent waits for the server to send the resource, and then the agent processes the resource according to the fragment value. In the most common case, the agent scrolls a Web page down to the anchor element which has an attribute string equal to the fragment value. Other client behaviors are possible.

As a consequence, in some circumstances of URL redirection or display of intermediate pages (e.g., login screens) by the server, the browser may not be able to apply the fragment to the resource it ultimately receives from the server. Also, applications running on the server do not normally receive the fragment value with the rest of the URI, and are thus unable to take it into account when processing a request.

External links

Hypertext most often refers to text on a computer that will lead the user to other, related information on demand. Hypertext represents a relatively recent innovation to user interfaces, which overcomes some of the limitations of written text.
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string is an ordered sequence of symbols. These symbols are chosen from a predetermined set.

In programming, when stored in memory each symbol is represented using a numeric value.
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character is a unit of information that roughly corresponds to a grapheme, grapheme-like unit, or symbol, such as in an alphabet or syllabary in the written form of a natural language.

An example of a character is a letter, numeral, or punctuation mark.
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A resource, or system resource, is any physical or virtual component of limited availability within a computer system. Every device connected to a computer system is a resource. Every internal system component is a resource.
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Uniform Resource Identifier (URI), is a compact string of characters used to identify or name a resource. The main purpose of this identification is to enable interaction with representations of the resource over a network, typically the World Wide Web, using specific
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Uniform Resource Locator (URL) formerly known as Universal Resource Locator, is a technical, Web-related term used in two distinct meanings:
  • In popular usage, many technical documents, it is a synonym for Uniform Resource Identifier (URI);

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Hypertext most often refers to text on a computer that will lead the user to other, related information on demand. Hypertext represents a relatively recent innovation to user interfaces, which overcomes some of the limitations of written text.
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Number sign is one name for the symbol #, and is the preferred Unicode name for the codepoint represented by that glyph. The symbol is similar to the musical symbol sharp (♯). Several names for this symbol are used in the United States and Canada.
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HTML (Hypertext Markup Language)

File extension: .html, .htm
MIME type: text/html
Type code: TEXT
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Internet is a worldwide, publicly accessible series of interconnected computer networks that transmit data by packet switching using the standard Internet Protocol (IP). It is a "network of networks" that consists of millions of smaller domestic, academic, business, and government
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Extensible Markup Language

File extension: .xml
MIME type: application/xml, text/xml (deprecated)
Uniform Type Identifier: public.xml
Developed by: World Wide Web Consortium
Type of format: Markup language
Extended from: SGML
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XPointer is a system for addressing components of XML based internet media.

At the present time (late 2002), XPointer is divided among four specifications: a "framework" which forms the basis for identifying XML fragments, a positional element addressing scheme, a scheme for
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Resource Description Framework

File extension: .rdf
MIME type: application/rdf+xml
Developed by: World Wide Web Consortium
Type of format: semantic web
Container for: FOAF, SKOS, ...
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RDFS or RDF Schema is an extensible knowledge representation language, providing basic elements for the description of ontologies, otherwise called RDF vocabularies, intended to structure RDF resources.
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The Web Ontology Language (OWL) is a language for defining and instantiating Web ontologies.[1] An OWL ontology may include descriptions of classes, along with their related properties and instances.
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SKOS or Simple Knowledge Organisation System is a family of formal languages designed for representation of thesauri, classification schemes, taxonomies, subject-heading systems, or any other type of structured controlled vocabulary.
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An XML namespace is a W3C recommendation for providing uniquely named elements and attributes in an XML instance. An XML instance may contain element or attribute names from more than one XML vocabulary.
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A client is an application or system that accesses a (remote) service on another computer system known as a server by way of a network. The term was first applied to devices that were not capable of running their own stand-alone programs, but could interact with remote computers
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web server can mean one of two things:
  1. A computer program that is responsible for accepting HTTP requests from clients, which are known as web browsers, and serving them HTTP responses along with optional data contents, which usually are web pages such as HTML documents and

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A user agent is the client application used with a particular network protocol; the phrase is most commonly used in reference to those which access the World Wide Web, but other systems such as SIP uses the term user agent to refer to the user's phone.
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A web browser is a software application that enables a user to display and interact with text, images, videos, music and other information typically located on a Web page at a website on the World Wide Web or a local area network.
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The concept of Resource is primitive in the Web architecture, and is used in the definition of its fundamental elements. The term was first introduced to refer to targets of Uniform Resource Locators (URLs), but its definition has been further extended to include the referent of
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web server can mean one of two things:
  1. A computer program that is responsible for accepting HTTP requests from clients, which are known as web browsers, and serving them HTTP responses along with optional data contents, which usually are web pages such as HTML documents and

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The word attribute can refer to:
  • An attribute in philosophy, property, an abstraction of a characteristic of an entity or substance
  • An attribute in art, an object that identifies a figure, most commonly referring to objects held by saints - see emblem

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URL redirection, also called URL forwarding, domain redirection and domain forwarding, is a technique on the World Wide Web for making a web page available under many URLs.
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logging (or signing) in and out is the process by which individual access to a computer system is controlled by identification of the user in order to obtain credentials to permit access. It is an integral part of computer security.
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