Chapter 11. Creating Links
4.01 specification puts it simply and clearly: "A link is a
connection from one web resource to another." This ability to
link one document to another is what makes HTML unique among document
markup languages and is the key to its widespread popularity.
This chapter focuses on the HTML tags related to linking and building
relationships between documents. It includes uses for the anchor tag,
linking with imagemaps (both client- and server-side), affecting the
appearance of hyperlinks, creating links with non-web protocols, and
associating documents with the link tag.
11.1. Summary of Tags Related to Linking
In this section, browser support for each tag is noted to the right
of the tag name. Browsers that do not support the tag are grayed out.
Tag usage is indicated below the tag name. Start and end tags are
required unless otherwise noted. "Deprecated" means that
the tag or attribute is currently supported but is due to be phased
out of the HTML specification and is discouraged from use (usually in
favor of similar style sheet controls). The attributes listed for
each tag reflect those in common use. A more thorough listing of
attributes for each tag, according to the HTML 4.01 specification,
appears in Appendix A, "HTML Elements".
|<a>||NN 2, 3, 4, 6 MSIE 2, 3, 4, 5, 5.5, 6 HTML 4.01 WebTV Opera5|
Defines an anchor within the document. An
anchor is used to link to another document or web resource. It can
also serve to label a fragment within a document (also called a
named anchor), which serves as a destination anchor
for linking to a specific point in an HTML document.
The attributes labeled "HTML 4.01" are new to the HTML
4.01 specification and are generally supported only by Internet
Explorer 5.5 and higher and Netscape 6.
HTML 4.01. Assigns an access key (shortcut key
command) to the link. Access keys are also used for form fields. The
value is a single character. Users may access the element by hitting
Alt-key (PC) or Ctrl-key
HTML 4.01. Specifies the character encoding of
the target document. See Chapter 7, "Internationalization" for information on
- coords=x,y coordinates
HTML 4.01. Specifies the x,y coordinates for a
clickable area in an imagemap. HTML 4.0 proposes that client-side
imagemaps be replaced by an <object> tag
containing the image and a set of anchor tags defining the
"hot" areas (with shapes and coordinate attributes). This
system has not yet been implemented by browsers.
Specifies the URL of the destination HTML document or web resource
(such as an image, audio, PDF, or other media file).
Gives the link a unique name (similar to the name
attribute) so it can be referenced from a link, script, or style
sheet. It is more versatile than name, but it is
not as universally supported.
- hreflang=language code
HTML 4.01. Specifies the base language of the
target document. See Chapter 7, "Internationalization" for a list of two-letter language
Places a fragment identifier within an HTML document. Fragments are
discussed further in Section 11.3, "Linking Within a Document" in this chapter.
Establishes a relationship between the current document and the
target document. Common relationships include
index, and glossary.
Specifies the relationship from the target back to the source (the
opposite of the rev attribute).
HTML 4.01. Defines the shape of a clickable area
in an imagemap. This is only used in the <a>
tag as part of HTML 4.01's proposal to replace client-side
imagemaps with a combination of <object> and
<a> tags. This system has not yet been
implemented by browsers.
HTML 4.01. Specifies the position of the current
element in the tabbing order for the current document. The value must
be between 0 and 32767. It is used for tabbing through the links on a
page (or fields in a form).
Not supported by WebTV or Internet Explorer 2.0 and
earlier. Specifies the name of the window or frame in
which the target document should be displayed. For more information,
see Section 11.5, "Targeting Windows" in this chapter and
Section 14.5, "Targeting Frames" in Chapter 14, "Frames".
Specifies a title for the target document. May be displayed as a
- type=MIME type
Specifies the content type (MIME type) of the defined content.
To a local file:
To an external file:
To a named anchor:
To a named anchor in the current file:
To send an email message:
To a file on an FTP server:
|<area>||NN 2, 3, 4, 6 MSIE 3, 4, 5, 5.5, 6 HTML 4.01
The area tag is used within the
<map> tag of a client-side
imagemap to define a specific "hot"
(clickable) area. Client-side imagemaps are discussed later in this
Required. Specifies a short description of the
image that is displayed when the image file is not available.
Specifies a list of comma-separated pixel coordinates that define a
"hot" area of an imagemap. The specific syntax for the
coordinates varies by shape (see Section 11.6, "Imagemaps" later in this chapter).
Specifies the URL of the document or file that is accessed by
clicking on the defined area.
Defines a "mouse-sensitive" area in an imagemap for which
there is no action when the user clicks in the area.
Defines the shape of the clickable area.
|<base>||NN 2, 3, 4, 6 MSIE 2, 3, 4, 5, 5.5, 6 HTML 4.01 WebTV Opera5|
Specifies the base pathname for all relative URLs in the document.
Place this element within the <head> of the
Required. Specifies the URL to be used.
Defines the default target window for all links in the document.
Often used to target frames. (This attribute is not
supported in MSIE 2.0.)
|<link>||NN 4, 6 MSIE 2, 3, 4, 5, 5.5, 6 HTML 4.01
Defines a relationship between the current document and another
document. This tag goes within the <head>
portion of the document. It is often used to refer to an external
Identifies the target document.
Identifies the target medium for the linked document so an alternate
style sheet can be accessed. The media attribute is explained in more
detail in Chapter 5, "Printing from the Web".
Describes the relationship from the current source document to the
target. Common relationship types include
index, and glossary.
Specifies the relationship of the target document back to the source
(the opposite of the rel attribute).
Provides a title for the target document.
Shows the type of an outside link. The value
text/css indicates that the linked document is an
external cascading style sheet.
|<map>||NN 2, 3, 4, 6 MSIE 2, 3, 4, 5, 5.5, 6 HTML 4.01 WebTV Opera5|
Encloses client-side imagemap specifications. Client-side imagemaps
are discussed later in this chapter.
Gives the imagemap a name that is then referenced within the
<img> tag. This attribute is required.
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