Information Technology Reference
In-Depth Information
In case you are interested in reviewing standards more closely,
you should note that the World Wide Web Consortium maintains a
general Web site at
http://www.w3.org.
As a further resource, the
consortium provides a service that allows you to check whether any
Web page conforms to the international standards. For details, you
can consult
http://validator.w3.org.
Although HTML allows authors to write simple Web pages ac
cording to standards, Web authors also can utilize more elaborate
languages when writing their Web pages. These languages provide
more capabilities (such as animation), and standards exist for these
languages as well. Let's take a look at JavaScript, a common Web
page development language often used in association with HTML.
HTML allows browsers to interpret and format Web pages, but
the format and capabilities that it facilitates are static; that is, a Web
server sends information to a browser, and the browser displays this
information in a predefined format. Except for following instruc
tions for display, the browser does not process information, and ac
tivities (such as mouse movement) by a user do not affect the dis
play. Although this model works well for the basic communication
of information, it relies on the server for most processing, and there
fore represents
server-side processing
.
With serverside processing, changes in the Web page's display
require a threestep process: the browser sends information to the
server (perhaps after a user enters data), the server analyzes the new
information, and the server's response is sent back to the browser.
As this outline suggests, such activity has two potential problems:
the server must handle all processing, and the network must carry
traffic for even the simplest processing tasks. Thus serverside pro
cessing can place significant burdens on both servers and networks.
An alternative approach would be to allow a user's browser to han
dle some processing requests. For example, after filling out a form, the
browser might check that all boxes were completed before transmitting
the information along the network to the server. In this case, the
browser handles some error checking, and potential problems can be
corrected before the browser transmits any user requests to the server.
