HTML and CSS Reference
In-Depth Information
Using the
meta
Element to Reload a Web Page
Describing your document is not the only use of the
meta
element. As you learned
earlier, servers transmit Web pages using a communication protocol called HTTP. You
can add information and commands to this communication stream with the
http-equiv
attribute of the
meta
element. One common use of the
http-equiv
attribute is to force
browsers to refresh a Web page at timed intervals, which is useful for Web sites that pub-
lish scoreboards or stock tickers. For example, to automatically refresh a Web page every
60 seconds, you would apply the following
meta
element:
<meta http-equiv=”refresh” content=”60” />
Another use of the
meta
element is to redirect the browser from the current document
to a new document. This might prove useful to Gerry someday if he changes the URL
of his site's home page. As his readers get accustomed to the new Web address, he can
keep the old address online, automatically redirecting readers to the new site. The
meta
element to perform an automatic redirect has the general form
<meta http-equiv=”refresh” content=”
sec
;url=
url
” />
where
sec
is the time in seconds before the browser redirects the user and
url
is the
URL of the new site. To redirect users after fi ve seconds to the Web page at
http://www.
camshots.com
, you could enter the following meta element:
When redirecting a Web
site to a new URL, avoid
confusion by always
including text notifying
users that the page is
being redirected, and pro-
vide users several seconds
to read the text.
<meta http-equiv=”refresh” content=”5;url=
http://www.camshots.com” /
>
At this point, Gerry does not need to use the
meta
element to send data or commands
through the HTTP communication protocol. However, he will keep this option in mind if
he moves the site to a new address.
Gerry is happy with the Web site you've started. He'll continue to work on the site
and will come back to you for more assistance as he adds new pages and elements.
Session 2.2 Quick Check
1.
The CAMmap image map has a circular hotspot centered at the point (50, 75)
with a radius of 40 pixels pointing to the faq.htm fi le. Specify the code to create
a
map
element containing this circular hotspot.
2.
An inline image based on the logo.jpg fi le with the alternate text
CAMshots
needs to use the CAMmap image map. Specify the code to apply the image map
to the image.
3.
What are the fi ve parts of a URL?
4.
Specify the code to link the text
White House
to the URL
http://www.
whitehouse.gov
, with the destination document displayed in a new unnamed
browser window.
5.
Specify the code to link the text
University of Washington
to the FTP server at
ftp.uwash.edu
.
6.
Specify the code to link the text
President of the United States
to the e-mail
address
president@whitehouse.gov
.
7.
What attribute would you add to a hypertext link to display the tooltip
Tour the
White House
?
8.
Specify the code to add the description
United States Offi ce of the President
as
metadata to a document.
9.
Specify the code to automatically refresh your Web document every 5 minutes.
