Transcript Web browsers

AS Level ICT
Selection and use of appropriate
software: Web browsers
Web-related software
• With the exponential growth of Internet usage, the
need for specialist software that allows users to
interact with it has also grown
• The most common web-related software in use
includes:
– Web browsers
– Email software
– Website authoring software
Web browsers
• A web browser is software that interprets the
markup of files in HTML, formats them into Web
pages, and displays them to the user
• Examples of browsers include: Internet Explorer,
Netscape Navigator, and Firefox
Web browsers
Internet Explorer –
when opened, the
web browser will
either display a
blank page or will
open a pre-set
webpage (in this
example the Google
search engine web
page)
Web browsers
• It is possible to access any web page that has
been submitted by its creator to the World Wide
Web using a web browser unless:
– The web browser is installed on a network that
has been set up to exclude certain categories of
web page (e.g. game sites, web pages that
contain adware, pornography, community sites
[YouTube, MySpace, Facebook])
– The web browser is installed on a stand-alone
computer that has ‘parental control’ software
installed on it (e.g. Weblocker, K9, Spector Pro)
Web browsers
• It is possible for users to access email facilities via
a web browser
Web browsers
Clara.net is one
of many ISPs
(Internet service
providers)
Their customers
can access their
emails via a
portal from the
clara.net website
Web browsers
The webmail portal
allows access to an
ISP customer’s
emails
Web browsers
When the hotlink is
clicked …
Web browsers
… a login page
appears onscreen
Once their user
name and password
have been entered,
the customer can
access their emails
Email
• Despite the fact that most users can access their
emails via their web browser and their ISP’s
website, many prefer to use dedicated email
software (e.g. Outlook Express)
• Most email systems use SMTP (Simple Mail
Transfer Protocol – a protocol for sending email
messages) to send emails from one server to
another
Email
• The emails can then be retrieved with an email
client using either POP (Post Office Protocol) or
IMAP (Internet Message Access Protocol)
• The correct POP or IMAP server and SMTP server
have to be specified when email software is being
configured
Email
• Email software usually has a number of useful
facilities, including:
– Create – this allows the user to compose an
email
– Reply – this allows the user to compose a reply
to an email that has been received
– Search – this allows the user to search their
archive of sent and received emails by
originator, addressee, subject, or date
In this example, to
create an email
the user clicks
‘New’ and
… a new
window – where
the email can be
composed – is
launched
In this example, to
reply to an email
the user clicks the
‘Reply’ icon and
… a
new window –
where the reply
can be composed
– is launched
The ‘Search’ facility
enables the user to
search the ‘Inbox’ folder
for received emails by
originator, subject, or
date
The same facility can
be used to search
‘Drafts’, ‘Outbox’, and
‘Sent Items’ folder
Email
– Forward – this allows the user to send a copy of
a received email – often with a covering
message – to a third party
– Address book – this allows the user to save the
email addresses of people to whom they wish to
send emails or who have sent them emails (the
latter can be done automatically)
The ‘Forward’ option allows the user to
forward (i.e. send) a copy of an email
they have received to a third party
When the
‘Address book’
option is clicked,
clicked
… searchable
the
address book
appears on
screen
Email
– Groups – this is a section within the address
book where the user can group addressees
together, so that an email sent to the group will
go to everyone in the group; this can speed up
the time taken to send the same message to a
large number of people
– Attachments – this allows the user to attach
files or folders to an email so that copies of
documents, spreadsheets, photographs etc. can
be sent via the Internet to other people
Once an email
has been
composed, files
and folders can
be attached to it
by clicking the
‘Add Attachment’
icon
A new dialogue
box will then
appear, and by
using the ‘Browse’
facility, the file or
folder to be
attached to the
email can be
found and
…
attached
Search engines
• The most used search engines (e.g. Google,
Yahoo, Ask) are natural language interfaces that
allow the user to search the Internet
• They are crawler-based search engines (as
opposed to human powered directories) that create
their listings automatically
• They use special programs (‘crawler’ or ‘spider’
programs) to go through the World Wide Web
looking for and at websites that they can index
• Users can then search through what the ‘crawlers’
or ‘spiders’ have found and indexed
Search engines
• To search the World Wide Web using a search
engine, the user must create a query
• The query can be quite simple, a single word at
minimum
• Creating a more complex query requires the use of
Boolean operators that allow the user to refine and
extend the terms of the search
Search engines
• The Boolean operators most often seen are:
– AND – This ensures that all the words joined by
"AND" must appear in the web pages (N.B.
some search engines substitute "+" for AND)
– OR – This ensures that at least one of the word
joined by "OR" must appear in the web pages
– NOT – This ensures that the word or words
following "NOT" must not appear in the web
pages (N.B. some search engines substitute "-"
for NOT)
Search engines
– FOLLOWED BY – This ensures that one of the
word or words must be directly followed by the
other
– NEAR – This ensures that the word or words
must be within a specified number of words of
the other
– Quotation Marks – The words between the
quotation marks are treated as a phrase, and
that phrase must be found in the web page
Search engines – Comparison of
search results
The results of a
search using the
words ‘search’ and
‘engine’
Search engines – Comparison of
search results
The results of a
search using the
phrase ‘search
engine’
Search engines – Comparison of
search results
The results of a
search using the
phrase ‘search’
AND ‘engine’
Search engines – Comparison of
search results
• The results of these searches produced similar but
not identical results
• This is because of the way in which the Boolean
operators honed down the search, the last being
more precise than the first (211,000,000 results as
opposed to 66,500,000 results)
• It is also a reflection of the way in which web
designers have used particular design features to
ensure that their websites are prioritised by a
search engine
Search engines – Comparison of
search results
How many hits would a Google search produce for the
following search criteria?
crown woods school
crown AND woods AND school
“crown woods school”
Search criteria
‘crown’ ‘woods’ ‘school’
‘crown’ AND ‘woods’ AND ‘school’
“crown woods school”
Number of ‘hits’
292,000
14,500,000
8,820
Website design features
• Websites usually have one or more of the following
design features:
– Logo – this helps to identify the website,
particularly ones belonging to commercial or
government organisations
– Navigation – unless the website only has a
single web page, users will need to navigate
their way around the website; a navigation bar
(navbar) is a common method used to achieve
this
Website design features
– Search facility – this enables the user to find
something particular on the website; sometimes
search facilities will also enable the user to
undertake a full Internet search from within the
website
– Hotlinks – these are words or phrases that,
when clicked, lead the user to another part of the
website or the Internet
– Hotspots – these are images that, when clicked,
lead the user to another part of the website or
the Internet
Website design features
Logo
Navigation
Search
Hotlinks
Hotspots
Website design features
Logo
Navigation
Hotlinks
Website design features
Logo
Navigation
Hotlinks
Hotspots
Website design features
Logo
Navigation
Search
Hotspots
Hotlinks
Website design features
• Web designers also use frames or tables to layout
each webpage
• Frames enable a designer to set up a page that
actually shows several web pages at once; this is
usually done so that the Header and/or Footer
and/or Sidebar that are seen remain the same
whatever the main content of the web page is
showing
Website design features
This example shows fames being
used so that the main content of
the webpage covers most of the
screen whilst the website
navigation is in the sidebar frame
This example shows fames
being used so that three
different pages can be ‘nested’
together
Website design features
• Frames have tended to fall out of favour with web
designers over recent years because some web
browsers do not cope well with them
• Tables have tended to be used in place of frames
recently because they allow the web designer to
layout each webpage exactly how they want
visitors to see them, regardless of the web browser
that is being used or the screen resolution the web
page is being viewed at
Website design features
A web page
viewed at a
screen
resolution of
800 x 600
Website design features
A web page
viewed at a
screen
resolution of
1024 x 768
Website design features
A web page
viewed at a
screen
resolution of
1280 x 960
Website design features
• In this example, the web page has been optimised
for the 1024 x 768 resolution; when viewed at 800
x 600 the whole of the web page cannot be seen,
and when viewed at 1280 x 960 the web page has
stretched to fill the screen
• A web designer should take this into consideration
when designing a website, and the use of tables –
which can be pre-set to a particular width – is a
very useful tool for ensuring that their design is
WYSIWYG (What You See Is What You Get)
Web authoring software
• The language used to create web pages is HTML
(HyperText Markup Language)
• This is a relatively easy to learn programming
language that uses a mixture of natural language
and abbreviated commands and keyboard symbols
Web authoring software
Keyboard symbol
Abbreviated
command
Natural language
command
This example of HTML shows the use of natural
language and abbreviated commands and keyboard
symbols
Web authoring software
• Typing in HTML commands takes time, and it is far
quicker for a web designer to use web authoring
(or web design) software to create a web site
• The facility to create web pages exists in several
applications (e.g. Microsoft Word, Microsoft
Publisher) but specialist web authoring software
has more functions available for the web designer
to use
Web authoring software
• The following programs are commonly used by
web designers to create web pages:
– Microsoft FrontPage
– Macromedia Dreamweaver
– Serif WebPlus
Web authoring software
Microsoft FrontPage
Web authoring software
Macromedia
Dreamweaver
Web authoring software
Serif WebPlus
Web authoring software
• All the examples shown have similar functions that
make them effective web authoring software:
– The ability to add and format text (including
changing font size, font colour, line spacing, and
paragraph justification)
– The ability to create frames
– The ability to add and use tables so that the
layout can be WYSIWYG (What You See Is
What You Get), regardless of the screen
resolution of the viewer’s computer monitor
Web authoring software
– The ability to import data from other applications
(e.g. text that has been word-processed, images
that have been manipulated)
– The ability to add hyperlinks to other web pages
– The ability to anchor together different sections
on a web page
– The ability to add mailto links (i.e. a link that
automatically launches the viewer’s email
application so that they can create a preaddressed)
Web authoring software
– The ability to preview web pages before they are
uploaded
– The ability to test view the web page in different
web browsers
– The ability to allow the web designer to view –
and change where necessary – the HTML
created by the web authoring software
Web authoring software
– The ability to use cascading style sheets (CSS)
– this is a simple mechanism for adding style
(e.g. fonts, colours, spacing) to web pages
– The ability to create forms that can be used to
collect data; these can be used in conjunction
with databases
AS Level ICT
Selection and use of appropriate
software: Web browsers