| The Complete Guide to the SAS Output Delivery System |
An HTML link is a place in a document that allows you to jump to another specific
place in the same document or in another document. A browser typically highlights
the text that is between the tags that begin and end the link. When you click
on the highlighted text, the browser displays the text at the link target.
The browser might then display the contents of the target in the active window,
or it might open another browser window that displays the contents of the
target.
An HTML reference names a file for the browser to display.
When a browser reads a reference, it displays the referenced file as if it
were part of the file that it is displaying. You can't tell by looking at
the browser's display that some of the material is in the file that you are
actually viewing and that some is referenced.
When you use ODS, the software automatically creates
the links and references that you need. You can, however, customize these
links to some extent. If you wish to do so, you will need to understand how
HTML implements links and references.
Note:
This simplified discussion of HTML links and references is designed
to provide information that will help you understand what ODS does when it
builds links and references for you. For a complete discussion of HTML tagging,
consult one of the many reference books that are available on the subject. ![[cautend]](../common/images/cautend.gif)
Each link in HTML is implemented with a combination of two sets
of <A> (anchor) tags. One anchor tag, which is the starting point of the
link, has an HREF attribute that identifies the anchor tag to link to. The
other anchor tag, which is the target of the link, has a NAME attribute. This
NAME attribute is what the HREF attribute in the first anchor tag points to.
The value of each NAME attribute in a file must be unique so that each value
of HREF points to a single, unambiguous location. The following figure illustrates
linking within a file:
Linking within a File
The important features at the starting point of this
link are
When a link points to a target outside the file that
is being displayed, the HREF attribute must include the path to that file.
The path can be the path within the file system or the uniform resource locator
(URL) of the file. The following figure illustrates a link from one file to
another file that is specified with a URL:
Linking to Another File
The important features at the starting point (the
anchor)
of the link are
ODS provides features that enable you to customize the
text that precedes the pound sign and the text that follows the pound sign.
For information on how to do this, see the discussions of HTML-file-specification,
ANCHOR=, BASE=,
PATH=,
and GPATH= as well as
How ODS Constructs Links and References.
HTML implements references in much the same way as it
implements links. The main difference is that a link points to a particular
location within a file and that a reference points to the file itself. HTML
uses the SRC attribute to identify a file to reference. The value of the SRC
attribute is constructed the same way that the value of the HREF attribute
is constructed except that there is no pound sign and no text following it.
Several options in the ODS HTML statement affect how ODS constructs
the links and references that point from the frame to the table of contents,
table of pages, and body file and from the table of contents or table of pages
to the body file. Links are made as HREF attributes on <A> (anchor) tags
inside the HTML files. Each HREF attribute points to the NAME attribute on
another <A> tag. The HREF must identify both the file that contains the
target and the name of the anchor within that file. The value of HREF must
be a valid target in a valid URL. It uses the following form:
|
<A href="URL#anchor-name">
|
ODS constructs the value
of an HREF attribute based on information
that you provide in the ODS HTML statement.
Note:
HTML
references to files use other tags, but the logic for creating the string
that identifies the file is the same as the logic for creating an HREF attribute
(see Implementing HTML Links and References).
The URL in an HREF attribute is composed of information
from three options in the ODS HTML statement: the BASE option; the GPATH=
or the PATH= option; and the BODY=, the CONTENTS=, or the PAGE= option.
-
If you specify BASE=, the value of that option
is the first part of the URL for every HREF attribute that ODS writes.
-
If you specify GPATH= or PATH=, the next part
of the URL in an HREF attribute comes from that option.
If the file that you are linking to is a high-resolution
graphic, ODS uses information from the GPATH= option as the next part of the
HREF. (For information on these options, see the discussion of GPATH= and the discussion
of PATH=.) The following table shows how ODS uses information from the GPATH=
option in the URL in HREF attributes:
If the file that you are linking
to is not a high-resolution
graphic, ODS uses information from the PATH= option as the next part of the
HREF. The following table shows how ODS uses information from the PATH= option
in the URL in HREF attributes:
Note:
If you use a fileref as the file
specification
in the BODY=, CONTENTS=, or PAGE= option in the ODS HTML statement, and you
do not use the URL= suboption in that option, ODS does not use information
from GPATH= or PATH= when it creates the complete URL for any corresponding
HREF attributes.
-
The last part of the URL that is used in an HREF
attribute is, by default, the name of the file that contains the target.
ODS determines the name of the file from the file-specification that you use in the BODY=, CONTENTS=, or PAGE= option. (ODS
does not create links or references to frame files.) For more information
on these options, see the discussion of HTML-file-specification.)
If you specify the URL=
suboption in one of these options,
ODS uses the string that you specify instead of the file name.
Note:
If you use a fileref as the file specification
and do not use the URL= suboption, ODS does not use information from GPATH=
or PATH= when it creates the complete
URL for the HREF attribute.
The anchor-name comes from
the value of the ANCHOR= option.
The following figure illustrates the creation of the
HREF:
Creating the Value of an HREF Attribute
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Copyright © 1999 by SAS Institute Inc., Cary, NC, USA. All rights reserved.
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