HTML and CSS Reference
In-Depth Information
6.7. Relationships
Very few documents stand alone. Instead, a document is usually part of
a collection of documents, each connected by one or several of the hy-
pertext strands we describe in this chapter. One document may be a part
of several collections, linking to some documents and being linked to by
others. Readers move among the document families as they follow the
links that interest them.
When you link two documents, you establish an explicit relationship
between them. Conscientious authors use the
rel
attribute of the
<a>
tag
to indicate the nature of the link. In addition, two other tags may be used
within a document to further clarify the location of a document within
a document family and its relationship to the other documents in that
family. These tags,
<base>
and
<link>
, are placed within the body of the
<head>
tag. [
<head>, 3.7.1
]
6.7.1. The <base> Header Element
As we previously explained, URLs within a document can be either abso-
lute (with every element of the URL explicitly provided by the author) or
relative (with certain elements of the URL omitted and supplied by the
browser). Normally, the browser fills in the blanks of a relative URL by
drawing the missing pieces from the URL of the current document. You
can change that with the
<base>
tag.
