In addition to general purpose elements such as paragraphs and lists,
HTML documents can express hyperlinks. An HTML user agent allows the
user to navigate these hyperlinks.
A hyperlink is a relationship between two anchors, called the head
and the tail of the hyperlink[DEXTER]. Anchors are identified by an
anchor address: an absolute Uniform Resource Identifier (URI),
optionally followed by a '#' and a sequence of characters called a
fragment identifier. For example:
In an anchor address, the URI refers to a resource; it may be used in
a variety of information retrieval protocols to obtain an entity that
represents the resource, such as an HTML document. The fragment
identifier, if present, refers to some view on, or portion of the
resource.
Each of the following markup constructs indicates the tail anchor of
a hyperlink or set of hyperlinks:
<A> elements with HREF present.
<LINK> elements.
<IMG> elements.
<INPUT> elements with the SRC attribute present.
<ISINDEX> elements.
<FORM> elements with `METHOD=GET'.
These markup constructs refer to head anchors by a URI, either
absolute or relative, or a fragment identifier, or both.
In the case of a relative URI, the absolute URI in the address of the
head anchor is the result of combining the relative URI with a base
absolute URI as in [RELURL]. The base document is taken from the
document's <BASE> element, if present; else, it is determined as in
[RELURL].
