HTML Tutorial 2 Hyperlinks - Doral Academy Preparatory
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Transcript HTML Tutorial 2 Hyperlinks - Doral Academy Preparatory
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New Perspectives
on Creating Web
Pages with HTML
Adding Hypertext Links to a Web Page
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Objectives
Create hypertext links between elements within
a Web page
Create hypertext links between Web pages
Review basic Web page structures
Create hypertext links to Web pages on the
Internet
Distinguish between and be able to use absolute
and relative pathnames
Create hypertext links to various Internet
resources, including FTP servers and
newsgroups
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Creating a Hypertext Document
Hypertext documents contain hypertext links,
items that you can select to view another topic or
document, often called the destination of the
link.
These links can point to:
another section on the same document
to a different document
to a different Web page
to a variety of other Web objects
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Opening A Web Page
This figure shows
that a browser
may only show a
portion of the
web page. The
user must scroll
down to see the
rest of the web
page.
vertical scroll bar
horizontal scroll
bar can also be
shown
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Adding Hypertext Links
You can place
hypertext links at
the top of a web
page to make it
easier for the
user to navigate
to a particular
section of the
document instead
of scrolling.
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Creating Anchors
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The <a> tag creates an anchor, text that is specially
marked so that you can link to it from other points in a
document.
Text that is anchored is the destination of a link; it is not
the text you click on.
Each anchor has its own anchor name, using the “name”
attribute i.e. <a name=“cc”>Classes</a>.
An anchor doesn’t have to be text. You can mark an
inline image as an anchor.
Adding an anchor does not change your document’s
appearance in any way. It merely creates locations in
your Web page that become destinations of links.
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Creating Anchors
Internal hyperlinks required
two steps:
Enter an anchor tag using a
# before the name of the
target location.
Define where the link will
take you (the target location)
with the NAME attribute.
<HTML>
<TITLE>Text</TITLE>
<BODY>
<A HREF=“#POWERFUL”>
Powerful Lines</A>
<P>Text</P>
<P>Text</P>
<P>Text</P>
<A NAME=“POWERFUL”>
Powerful Lines</A>
</BODY>
</HTML>
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Hyperlinks Inside Your Document
Internal hyperlinks
jump from an index to
content below, in
another spot on a
Web page.
Internal
hyperlink
Jumps to content
below
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How an Anchor Works
hypertext links
When the user clicks
one of the hypertext
links, the link will go
directly to that section
(anchor, which is the
destination of the link)
within the web page.
anchor
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Creating Links
To create a link to an anchor, use the same <a> tag you used to
create the anchor.
The <a> tags used to create links are sometimes called link
tags.
Use the href attribute, which is short for Hypertext Reference, to
indicate the location to jump to.
href can refer to an anchor that you place in the document or
to a different Web page or a resource anywhere on the
Internet
it is important to note that the href attribute is case sensitive
You link to an anchor using the anchor name preceded by a
pound (#) symbol i.e. <a href=“#gra”>Grading</a>.
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Creating Links Continued
After you create
the anchors that
serve as
destinations for
your links, you
need to create the
links themselves.
You should be careful to make
each anchor name unique within a
document.
The <a> tag
you use to create
the anchor and
the href
attribute to
indicate the
location to jump
to.
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Text Links in the Browser
If the headings do
not appear as text
links, check your
code to make sure
that you are using
the <a> and </a>
tags around the
appropriate text,
the href attribute
within the tag, and
the quotes and #
symbols.
Text formatted as links
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Web Page Structures
Storyboarding your Web pages before you
create links helps you determine which
structure works best for the type of information
you’re presenting.
You want to ensure that readers can navigate
easily from page to page without getting lost.
You’ll encounter several Web structures as
you navigate the Web.
Examining some of these structures can help
you decide how to design your own system of
Web pages.
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Linear Structures
This figure shows one common Web page structure, the linear structure, in which each
page is linked to the next and to previous page, in an ordered chain of pages.
Link to
previous page
In this structure
you can jump
only from one
page to the next
or previous page
Link to next page
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Augmented Linear Structure
This figure shows an augmented linear structure, in which you include a link in each
page that jumps directly back to the first page, while keeping the links that allow you
to move to the next and previous pages.
first link jumps to
previous page
third page has three links
second link jumps back to beginning
third link
jumps to next
page
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Hierarchical Structure
This figure shows the
hierarchical structure,
which starts with a
general topic that
includes links to more
specific topics. Each
specific topic includes
links to yet more
specialized topics, and
so on.
In a hierarchical
structure, users can
move easily from
general to specific and
back, but not from
specific to specific.
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Hierarchical Structure on
AltaVista Web Page
As with the linear
structure, including a link
to the top of the structure
on each page gives users
an easy path back to the
beginning.
Subject catalogs such as
the AltaVista directory of
Web pages often use this
structure. This figure
shows this site, located at
http://www.altavista.com.
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Combination of Linear and
Hierarchical Structures
This figure shows a hierarchical structure in which each level of
pages is related in a linear structure.
information about the play
information
about the
acts
each level
is linear
the scenes
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Web Structures Continued
A little foresight can go a long way toward
making your Web pages easier to use.
The best time to organize a structure is
when you first start creating pages, when
those pages are small in number and
more easily managed.
If you’re not careful, your structure can
become confusing and unmanageable for
the user.
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Multipage Document with
No Coherent Structure
This structure is
confusing, and it makes it
difficult for readers to
grasp the contents of the
overall Web site.
Moreover, a user who
enters this structure at a
certain page might not be
aware of the presence of
the other pages.
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Creating Links Among
Documents
Unlike creating hypertext
links between elements on
the same page, this process
does not require you to set
an anchor in a file to link
to it; the filename serves as
the anchor or destination
point.
links to the
conttxt.htm
document,
which contains
contact
information
the chem.htm
document, which is
the document
containing the links.
links to the
linktxt.htm
document, which
contains links to
various Chemistry
Web sites.
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Linking to a Document
To create a link to a document, use the
same <a> tag with the href attribute i.e. <a
href=“contact.htm”>Contact
me</a>.
In order for the browser to be able to
locate and open contact.htm, it must be in
the same folder as the document
containing the link.
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HTML Code that
Links to Other Documents
<a> tags to
point to other
documents
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Browser Displaying Links
to Other Documents
links to the Contact and Links page
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Linking to a Section of a
Document
To navigate to a specific location elsewhere in a document, rather than
the top, you can set anchors and link to an anchor you create within
the document.
for example, to create a link to a section in the Web page
home.htm marked with an anchor name of “interests,” you create
an anchor in home.htm in the section on Interests, and then enter
the following HTML code in the current document:
<a href=“home.htm#interests”> View my interests
</a>
the entire text, “View my interests,” is linked to the Interests
section in the home.htm file, via the anchor name “interests”
the pound symbol (#) in this tag distinguishes the filename from
the anchor name
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Adding Links to Specific
Locations in a Page
The pound symbol
(#) in these tags
(shown in red)
distinguishes the
filename from the
anchor name.
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Links in the Chemistry Page that
Point to Anchors in the Links Page
links
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Linking to Documents
in Other Folders
Browsers assume that if no folder
information is given, the file is in the same
folder as the current document.
When referencing a file located in a
different folder than the link tag, you must
include the location, or path, for the file.
HTML supports two kinds of paths:
absolute paths and relative paths.
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Absolute Pathnames
An absolute pathname provides a precise location for a
file.
With HTML, absolute pathnames begin with a slash (/) and
are followed by a sequence of folders beginning with the
highest level folder and proceeding to the folder that
contains the file.
Each folder is separated by a slash.
After you type the name of the folder or folders that
contains the file, type a final slash and then the filename
itself i.e. /tutorial.02/case/parks.htm.
HTML also requires you to include the drive letter followed
by a vertical bar (|) i.e. /C|/tutorial.02/case/parks.htm.
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Folder Tree
This figure shows five
HTML files that are
located in four different
folders.
The top most folder is the
tutorial.02 folder. Within
the tutorial.02 folder are
the tutorial and case1
folders, and within the
case1 folder is the extra
folder.
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Absolute Pathname
This figure shows absolute pathnames for five HTML files.
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Relative Pathnames
A relative path specifies the location for a file in relation
to the folder containing the current Web document.
As with absolute pathnames, folder names are separated
by slashes.
Unlike absolute pathnames, a relative pathname does
not begin with a slash.
To reference a file in a folder directly above the current
folder in the folder hierarchy, relative pathnames use two
periods (..) i.e. ../tutorial/chem.htm.
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Relative Pathnames Continued
Relative pathnames make your hypertext
links portable.
Unlike absolute pathnames, If you move
your files to a different computer or server,
the hypertext links will stay intact.
If absolute pathnames are used, each link
has to be revised. This can be a very
tedious process.
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Relative Pathnames
This figure shows the relative pathnames and their interpretations
for HMTL files and how they would be displayed.
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Linking to Documents on the
Internet
To create a hypertext link to a document on the Internet, you
need to know its URL.
A URL, or Uniform Resource Locator, specifies a precise
location on the Web for a file.
You can find the URL of a Web page in the Location or
Address box of your browser’s document window.
Once you know a document’s URL, you can create a link to
it by adding the URL to the <a> tag along with the href
attribute in your text file i.e. <a href=“
http://www.mwu.edu/course/info.html”>Course
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Information</a>.
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Uniform Resource Locator
(URL)
Each URL follows the same format.
The first portion of the URL identifies the
communication protocol, which is a set of rules that
governs how information is exchanged.
Web pages use the communication protocol HTTP,
short for Hypertext Transfer Protocol, so all Web
page URLs begin with the letters “http”.
Following the communication protocol, there is
typically a separator, such as a colon and two slashes
(://) i.e. http://www.mwu.edu.
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Interpreting Parts of a
Uniform Resource Locator (URL)
This figure interprets a Web page with the URL
http://www.mwu.edu/course/info.html#majors.
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Link to Another Page on the
Web
As long as your
computer is
connected to the
Internet, clicking
the text within the
tag navigates you
to the document
located at the
specified URL.
Links to the College Board AP Internet page
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College Board AP Page
Chemistry page
remains open in
the original
browser window
AP page in a
separate browser
window
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Displaying Linked Documents
in a New Window
By default, each Web page you open is displayed in the
main browser window, replacing the one you were viewing
last.
To force a document to appear in a new window, instead
of the main browser window, you would use the target
attribute in the href tag i.e. <a href=“url”
target=“new_window”>Hypertext</a>
url
is the URL of the page, and new_window is a
name assigned to the new browser window
the value use for the target attribute is used by the
browser to identify the different open windows in the
current browser session
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External Hyperlinks
You can set up external hyperlinks to open in the same
browser window by using the same value for the target
attribute.
if you do, the first hyperlink clicked opens the new window
and displays the contents of the external file
as subsequent external hyperlinks are clicked, they replace
the contents of the already opened window, and the contents
of the main browser window remain unaffected
If you want your external documents to be displayed in their
own browser window, you can assign a unique target value for
each hyperlink, or you can assign the _blank keyword to the
target attribute i.e.
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<a href=“url” target=_blank>Hypertext</a>.
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Linking to File Transfer Protocol
(FTP) Servers
You can create links to other Internet resources, such as
FTP (File Transfer Protocol) servers.
FTP servers can store files that Internet users can
download, or transfer, to their computers
FTP is the communications protocol these file servers
use to transfer information
URLs for FTP servers follow the same format as
those for Web pages, except that they use the FTP
protocol rather than the HTTP protocol i.e.
<a href=
ftp://ftp.microsoft.com>Microsoft FTP
server</a>.
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Displaying a FTP Site
Different browsers can display the contents of an FTP site in different ways.
This figure shows what it might look like with Internet Explorer.
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Linking to Usenet News
Usenet is a collection of discussion forums
called newsgroups that let users exchange
messages with other users on a wide variety of
topics.
The URL for a newsgroup is news:newsgroup.
To access the surfing newsgroup alt.surfing, you
place this line in your HTML file i.e. <a
href=news:alt.surfing>Go to the
surfing newsgroup</a>.
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Accessing the alt.surfing
Newsgroup
When you click a
link to a newsgroup,
your computer
starts your
newsgroup software
and accesses the
newsgroup.
This figure shows
an example of the
Outlook
Newsreader
program.
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Linking to E-mail
Many Web designers include their e-mail addresses on
their Web pages, so that users who access the page can
send feedback.
You can identify e-mail addresses as hypertext links.
when a user clicks the e-mail address, the browser starts
a mail program and automatically inserts the e-mail
address into the “To” field of the outgoing message
The URL for an e-mail address is mailto:e-mail_address.
To create a link to the e-mail address [email protected], the
following code would be entered
<a href=mailto:[email protected]>[email protected]</a>
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Mail Message Window
window opens
when the
[email protected]
link is clicked
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Adding an Email Link
the address
itself is in the
code for the
mailto: URL
mail message
window opens
with e-mail
address already
inserted
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Coloring Text
You will use three separate
attributes to color text :
Use the text attribute to
change color of text
Use the hypertext link color
attribute to change color of
hypertext links
Use the visited link attribute
to change color of hypertext
links that have been selected
<HTML>
<TITLE>Text</TITLE>
<BODY
TEXT=BLUE
LINK=RED
VLINK=GREEN>
<P>Text</P>
<P>Text</P>
<P>Text</P>
</BODY>
</HTML>
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Coloring Text
<HTML>
<TITLE>Text</TITLE>
<BODY
TEXT=BLUE
LINK=RED
VLINK=GREEN>
<P>Text</P>
<P>Text</P>
<P>Text</P>
</BODY>
</HTML>
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Summary
•
Learned how to work with hypertext links.
• Learned how to create anchors within a Web
page.
Created links to anchors.
• Created hyperlinks within a single
document and links to other Web pages.
• Discussed creating hyperlinks to
resources other than Web pages,
such as FTP sites, e-mail addresses
and Gopher servers.
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