A
web page (or webpage) is a web document that is suitable for
the World Wide Web and the web browser. A web browser displays a web
page on a monitor or mobile device. The web page is what displays, but the
term also refers to a computer file, usually written in HTML or comparable
markup language, whose main distinction is to provide hypertext that will
navigate to other web pages via links. Web browsers coordinate web
resources centered around the written web page, such as style sheets,
scripts and images, to present the web page.
On a network, a web browser can
retrieve a web page from a remote web server. On a higher level, the web
server may restrict access to only a private network such as a corporate
intranet or it provide access to the World Wide Web. On a lower level, the
web browser uses the Hypertext Transfer Protocol (HTTP) to make such
requests.
A static web page is
delivered exactly as stored, as web content in the web server's file system,
while a dynamic web page is generated by a web application that is
driven by server-side software or client-side scripting. Dynamic web pages
help the browser (the client) to enhance the web page through user input to
the server.
Colour,
typography, illustration, and interaction
Web pages usually include
information as to the colours of text and backgrounds and very often also
contain links to images and sometimes other types of media to be included in
the final view. Layout, typographic and color-scheme information is provided
by Cascading Style Sheet (CSS) instructions, which can either be embedded in
the HTML or can be provided by a separate file, which is referenced from
within the HTML. The latter case is especially relevant where one lengthy
stylesheet is relevant to a whole website: due to the way HTTP works, the
browser will only download it once from the web server and use the cached
copy for the whole site.
Images are stored on the web
server as separate files, but again HTTP allows for the fact that once a web
page is downloaded to a browser, it is quite likely that related files such
as images and stylesheets will be requested as it is processed. An HTTP 1.1
web server will maintain a connection with the browser until all related
resources have been requested and provided. Web browsers usually render
images along with the text and other material on the displayed web page.
Dynamic behavior
Client-side computer code such as
JavaScript or code implementing Ajax techniques can be provided either
embedded in the HTML of a web page or, like CSS stylesheets, as separate,
linked downloads specified in the HTML. These scripts may run on the client
computer, if the user allows.
Browsers
A web browser can have a Graphical
User Interface, like Internet Explorer, Mozilla Firefox, Chrome and Opera,
or can be text-based, like Lynx or Links.
Web users with disabilities often
use assistive technologies and adaptive strategies to access web pages.
Users may be color-blind, may or may not want to use a mouse perhaps due to
repetitive stress injury or motor-neurone problems, may be deaf and require
audio to be captioned, may be blind and using a screen reader or braille
display, may need screen magnification, etc.
Disabled and able-bodied users may
disable the download and viewing of images and other media, to save time,
network bandwidth or merely to simplify their browsing experience. Users of
mobile devices often have restricted displays and bandwidth. Anyone may
prefer not to use the fonts, font sizes, styles and color schemes selected
by the web page designer and may apply their own CSS styling to the page.
The World Wide Web Consortium (W3C) and Web Accessibility Initiative (WAI)
recommend that all web pages should be designed with all of these options in
mind.
Elements
A web page, as an
information set, can contain numerous types of information, which is able to
be seen, heard or interact by the end user:
Perceived (rendered) information:
·
Textual information: with diverse render variations.
·
Non-textual information:
o
Static images may be
raster
graphics, typically GIF, JPEG or PNG; or vector formats such as SVG or
Flash.
o
Animated images typically
Animated
GIF and
SVG, but also may be Flash,
Shockwave, or Java applet.
o
Audio, typically MP3, ogg or
various proprietary formats.
o
Video, WMV (Windows), RM (RealMedia),
FLV (Flash Video), MPG, MOV (QuickTime)
·
Interactive information:
o
For "on page" interaction:
§
Interactive text: see DHTML.
§
Interactive illustrations: ranging from "click to play"
images to games, typically using script orchestration, Flash, Java
applets, SVG, or Shockwave.
§
Buttons: forms providing alternative interface, typically for use with script
orchestration and DHTML.
o
For "between pages" interaction:
§
Hyperlinks: standard "change page" reactivity.
§
Forms: providing more interaction with the server and server-side databases.
Internal (hidden) information:
·
Comments
·
Linked Files through Hyperlink
(Like DOC, XLS, PDF, etc.)
·
Metadata with
semantic meta-information, Charset information, Document Type Definition
(DTD), etc.
·
Diagramation and style information: information about rendered items (like image size attributes) and visual
specifications, as Cascading Style Sheets (CSS).
·
Scripts,
usually JavaScript, complement interactivity and functionality.
Note: on server-side the web page may also have "Processing Instruction
Information Items".
The web page can also contain
dynamically adapted information elements, dependent upon the rendering
browser or end-user location (through the use of IP address tracking and/or
"cookie" information). From a more general/wide point of view, some
information (grouped) elements, like a navigation bar, are uniform for all
website pages, like a standard. These kind of "website standard information"
are supplied by technologies like web template systems.
Rendering
Web pages will often require more
screen space than is available for a particular display resolution. Most
modern browsers will place a scrollbar (a sliding tool at the side of the
screen that allows the user to move the page up or down, or side-to-side) in
the window to allow the user to see all content. Scrolling horizontally is
less prevalent than vertical scrolling, not only because such pages often do
not print properly, but because it inconveniences the user more so than
vertical scrolling would (because lines are horizontal; scrolling back and
forth for every line is much more inconvenient than scrolling after reading
a whole screen; also most computer keyboards have page up and down keys, and
many computer mice have vertical scroll wheels, but the horizontal scrolling
equivalents are rare). When web pages are stored in a common directory of a
web server, they become a website.
A website will typically contain a
group of web pages that are linked together, or have some other coherent
method of navigation. The most important web page to have on a website is
the index page. Depending on the web server settings, this index page can
have many different names, but the most common is index.html. When a browser
visits the homepage for a website, or any URL pointing to a directory rather
than a specific file, the web server will serve the index page to the
requesting browser. If no index page is defined in the configuration, or no
such file exists on the server, either an error or directory listing will be
served to the browser. A web page can either be a single HTML file, or made
up of several HTML files using frames or Server Side Includes (SSIs).
Frames have been known to cause
problems with web accessibility, copyright, navigation, printing and search
engine rankings, and are now less often used than they were in the 1990s.
Both frames and SSIs allow certain content which appears on many
pages, such as page navigation or page headers, to be repeated without
duplicating the HTML in many files. Frames and the W3C recommended
alternative of 2000, the <object> tag, also allow some content to remain in
one place while other content can be scrolled using conventional scrollbars.
Modern CSS and JavaScript client-side techniques can also achieve all of
these goals and more.
When creating a web page, it is
important to ensure it conforms to the World Wide Web Consortium (W3C)
standards for HTML, CSS, XML and other standards. The W3C standards are in
place to ensure all browsers which conform to their standards can display
identical content without any special consideration for proprietary
rendering techniques. A properly coded web page is going to be accessible to
many different browsers old and new alike, display resolutions, as well as
those users with audio or visual impairments.
URL\Uniform Resource Locator
Typically, web pages today are
becoming more dynamic. A dynamic web page is one that is created server-side
when it is requested, and then served to the end-user. These types of web
pages typically do not have a permalink, or a static URL, associated with
them. Today, this can be seen in many popular forums, online shopping, and
even on Wikipedia. This practice is intended to reduce the amount of static
pages in lieu of storing the relevant web page information in a database.
Some search engines may have a hard time indexing a web page that is
dynamic, so static web pages can be provided in those instances.
Viewing
In order to graphically display a
web page, a web browser is needed. This is a type of software that can
retrieve web pages from the Internet. Most current web browsers include the
ability to view the source code. Viewing a web page in a text editor will
also display the source code.
Creation
To create a web page, a text
editor or a specialized HTML editor is needed. In order to upload the
created web page to a web server, traditionally an FTP client is needed.
The design of a web page is highly
personal. A design can be made according to one's own preference, or a
premade web template can be used. Web templates let web page designers edit
the content of a web page without having to worry about the overall
aesthetics. Many people publish their own web pages using products like
Tripod, or Angelfire. These web publishing tools offer free page creation
and hosting up to a certain size limit. Other ways of making a web page is
to download specialized software, like a Wiki, CMS, or forum. These options
allow for quick and easy creation of a web page which is typically dynamic.
Saving
While one is viewing a web page, a
copy of it is saved locally; this is what is being viewed. Depending on the
browser settings, this copy may be deleted at any time, or stored
indefinitely, sometimes without the user realizing it. Most GUI browsers
provide options for saving a web page more permanently. These may include:
·
Save the rendered text without
formatting or images, with hyperlinks reduced to plain text
·
Save the HTML as it was served —
Overall structure preserved, but some links may be broken
·
Save the HTML with relative links
changed to absolute ones so that hyperlinks are preserved
·
Save the entire web page — All
images and other resources including stylesheets and scripts are downloaded
and saved in a new folder alongside the HTML, with links to them altered to
refer to the local copies. Other relative links changed to absolute
·
Save the HTML as well as all
images and other resources into a single MHTML file. This is supported by
Internet Explorer and Opera. Other browsers may support this if a suitable
plugin has been installed.
Most operating systems allow
applications such as web browsers not only to print the currently viewed web
page to a printer, but optionally to "print" to a file that can be viewed or
printed later. Some web pages are designed, for example by use of CSS, so
that hyperlinks, menus and other navigation items, which will be useless on
paper, are rendered into print with this in mind. Sometimes, the destination
addresses of hyperlinks may be shown explicitly, either within the body of
the page or listed at the end of the printed version. Web page designers may
specify in CSS that non-functional menus, navigational blocks and other
items may simply be absent from the printed version. |