Tu&"relr
nfrW*d:rreilrg
Teehrrmlcgf
es [ \efebffiesrgrt
-J-"**
DIrectfro,ns:
Amswen
questloms"
the fofllowlng
L" Whatisthe diffenence
between
the Webandthe lnternet?
2. Acconding
to TirilBerners-Lee,
what isthe Weh?
3. A Webpageisa docunrent
thatcontains
what4 components?
4. Whatis a browsen?
5 . W h a t i s a l i n k ?W h a tc a ni t a N sboe c a l l e d ?W h o c o i n e dt h i st e r m ?
6. What doesURLstandfor?
7. Suppose'you
wentto the CNt\website.Togetthere,youenterhttp://www.cnn.com.
Accordingto
the
article,
whatcouldyoualsoenterintothe address
barthatwill alsotakevouto the site?
8. A URI-shouldnevercontain
evenaftera punctuation
mark.An
(or underscorei
is sometimesusedto givethe appearance
of a spacebetweenwords. Also
avoidusingcapitallettenswhen you createVourown rnaterials.
TURN OVER
WebDesignI Developed
by Mr.Schneider
I
-\
9" Vrfhatis a Web resource?
t
10. What is a Web serven?
whenthe serverlson?
running
to usewhatsoftware
that isalways
11. A Webserverisconfiguned
standfor?
12. What doesI-ITTP
13. What doesa HTTPstatuscodeindicate?
Lookat tableG-1:CommonHTTPstatuscodes.Fil[in the chartbelow.
E@DE
ft/rEssA6E
301
5Ue
303
404
5oCI
by Mr. SchneiderI
3 $ Wef DesignI Developed
DESERIPTflO!U
,
l/
t/
ri
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i.-
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:
, : - , , i i ' i r : ; , 1 , t - i it ,; i ;
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Thei'e
isa cliifei"encu"
ireiween
r'hewebaridrhe$nierniet.
Thelniernet
isa cornrr'rirr'ricailons
neiirryor{r
ihattransnritr
ciaia'
:nclulclino
email,
vi'ieon-rnf-erenices,
phone
rir;,,r.,,
cali:.
ar-rci
rfie55aEe::"
The
is
a
coller:ijrlr-:
Di
cic,cr-rrn"^91,,,r11*r'ltveb
pacles
ihaiar,:;rcct"sj€d
arierthelniernet
ancjarer.eiated
,byl,rsinc1
lir.:ks.
'.a'*1iii"-.r:{-::
Starting on the Internet o r<.eep,;rcTrtiit. t:,i
/r:iri i:;;iroi'i'ievV::: Siir: o liis.innhirC '/cui lii,:vt:ili
o 5e;iih:i';; ij:c litlsil o rjiiiir;,: jlri;
i-ii:i,.ii;";lo rililir:;t,
Ti?ii6i ,{i-.1;,*.;7;iir:;;l:,
o i,;f.iiii:iii-iq
i_i:n:ir:;-,i.it,-ie:;
l What fisthe Weh?!n thewordsof TirnBerners-Lee,
,,The
tA/orlcl
WideWebisanabstract
(imaginary)
:paceoi,infor_
rnation."
TheWeb,macie
up oi rnillions
of Websites,isthe
.ommoniermfoi.theWorldWicleWeb.A ili/:.;ir,
i,ir",.
iyo._
callycontains
a collection
of r.elatecl
Webpages.
,L What is a Weh page?,A ji:a:iiij,
L:;ir,rijrii
isa clocument
that
cancontain
texi,graphics,
rrideo,
anclaLrdio.
l_\Webpageis
an i',ll"jirlir,i)i,i,)i:tJj;jr-i,tiiji,:t!:-a
iext Or ASC|i CloCUmentWith
smbecldecl
HTii/Ltags.Sometagsspecifo
hovvtheclocur-nent
isio bedisplayecl,
suchaswheregraphics
sfroulcJ
be
placed,
howtextshoLrld
appear,
anclso0n,whenviewed
rna browser.
Othertagscontain
linksto relatecr
clocuments,
graphics,
sound,
andvideofiies.
j
tlianhin linl,
originated
beforeiheil/ebor e,renbeforetheInternet.
lt
surfaced
in themid-i960s,when Harvarcl
graduate
Ted
' Nelsoncoined
thet€fmlt.rl,;rir:i..;l:,,.i,1..
Her-isecl
ihistermto
describe
a computer
system
ihatcoulds,rore
iiierary
documents,
linkthemaccorcling
to logical
relationships,
ancl
allovir
readers
to commen.i
andannotate
whattheyreacl.
Clver
theyears,
thetechnologies
associatecl
withhyper_
texihavecontinued
to improve.
Today,
clicking
a linkon a
\A/eb
page-anr"rncjerlined
wordcr phrase,
or a graphic_
openstherelated
document.
Whenyouclicka link,you
movetc another
location
on thesameWebpageor to a
nevrr
Webpage.ThenewWebpagemightbepartof the
sameWebsite,or it mightbea newvVeb
site.Links
are
whatkeepWebpages
relatecl.
o Horwdo ! vfiewa Weh page?you usea browserro open
anCviewWebpages.
l\ ji,;;'5rixo;:;;
(sometimes
referrecj
to as
'tlhii
a
.h'1.'Lr*;i,irr)
issoftware
installed
onyour.ompui:er
thatdisplays
Webpageelements
andmanages
links
between
pages.
Popular
browsers
arel\zlicrosof.i
Internet
Explorel
Mozilla
Firefox,
Coogle
Chrome,
or AppleSafari.
Youusea browserto
access
a Webpageeiiherby typinoa
URLin theAddress
baror byclicking
a linkon theopen
page.Otherwaysto getto a Webpageinclude
click"//eb
inga linkin yourFavorites
list,if youhavealreac{y
bool<_
marl<ecl
it. l-avorites
wilibediscussed
in a iateriesson.
.I:; t..it]i.,:-1,i,-:
c What fisa URL?rlll,i!stands
forUniform
Resource
Starting
on thelnternet
Locaior.
Each
Webpagehasa unique
URL.
TheURListheaddress
for
:' What is a lflrnle?
A lii,;rt,'
(aisocallecl
i;i:r,.;rl;,iit,,:r,
or a
thaiWebpage.TheURLisusecl
to locatertsassociated
Web
,jrr
ii;iil) isa navigation
";il,.i:t':i::t:tii
tooion a Webpage.5ee
page.Forexample,
iheURLfortheCable
Nlews
Neiwork
Figure
C-'1.Linksarebased
on hypeftex.i,
whichisa key
(Citl[J)\A/eb
siteis http;//rnrrrnv.cnn.iom.
lVlost
URLs
begin
tonceptfor understanding
the\Aieb,
Theicleaof hvperte,yi withhttp://to indicate
theWeb's
standarcl
communications
'./Vheri
Irfctoc,:'.i,
frpirrga URL,;rottcioir,:rhavet,-'typel!-re
vvorll's
Adiife:t bat, sc v,rv'niv'i{:iii'aol-f:
brovrrset
tfre
i",,
itiip'.1I
c[ll'i.iolri,
i aisI,'iip://trrrvtrw.
iust asiir,el
your browsetand a VVebserver'ThecY:ieccirttrr'
liettrveerr
uesuntilthe \A/ebpageappeafsirryourbrowset'
C.WlmatiS a V,Vehs,e[l/er?l.':i;i:,i,,:,.:i':,''tii! a CorTtpu'Lei
ovei'ciie
that usesspeciaisofiwareio transntitWelipages
A"Jlll nevercoritain:
rr!'ethc rules fo,r' Ufl]t=s?'
c U,J[iirar'L
lniettre'i./: Web serveri: iorifigureoi-ouseFlTl'|l softw;l^e'
so oc ttot i:ypeany
sllaces,€verraftefa pliticiuatior'trtatl<.,
whenthe seryerison soihe Welr
wlrichis aiwaysrr.lntrirrg
useci
is sometirnes
spaceswithii'ra UFiL'Ar' underlines)/n-rb'ol
''
i"i':'i'it'' i''i;r''r":l';I
readytc f ulfill !"equestu'
serveris alu,'ays
words,for ellarrlof a spacebe.iweerr
io giverhe appearance
't.i,a,,jij1,,,,i,'
protocoluseo
ir'fi;,r11;,i..,,,i.;.
is ihe communicatiorrs
Besureto useihe cor
ple vwirw.detroi'i:.com/top-1O.htrnl.
porE i:
One of the server's
a fon/rardsiash(/)-anci ciuplica'te to transportdataoverthe Web.
reci type of slash-alwa)/s
iequesl
Wherr
a
for HTTPrequests
iistenrng
dedicated'io
arecase
exaciiy.SorneWebsen/ers
1l-i6URL'scapitalizatioi-r
.iheserversoftwat'eanal;r2s5
the requestarrcitalte:
arrives,
l-rtrnl
On theseser/eis,typingvrnrwv.cnru.edu/Info
sensitiire.
thal
'rheWebpaqethat's
it' The cornpu'ter
fulfill
to
actionis necessary
tvl-ratever
l) wili not iocate
(witir aii uppercase
whenyoutypea URLinto
theserules
i).Follow
lowercase
i:arc'fa browser,
theAcidress
runsoftware
mighiopeiate
a cornputer
ningon it aswell.Forexample,
Transfer'
andanFTP(File
anemailserver,
asa Webseryer,
these
allai thesametime'Toharrdle
server
Protocoi)
one
a computerdevotes porttc
duiiesefficiently,
diirerse
r'o5li4TP
erriail
Port80),ano'iher
(usually
HTfPrequests
(POP)
Protocol
Of{ice
for
Post
Porl25,or
(usually
requests
(usupori110),anda thirdto FTPrequests
usually
enrail,
reques'i
comr;pruter?'To
clo,Weh paE]esglct to lrni5lr
c' l-Norw
the
type
eiiher
viev4
tlreWebpagethatyouvvant'co irou
'/our
a linl<.
bar,or cliclq
Address
intothebrowser's
LJRL
page
fileassociateC
Web
the
for
request
a
browsercreates
'i;rped
Therequest
or thelinl<
you
withthe LIRL
1louclicked.
I aliyPort2Aor 21).
worlcin
HTTP
protocol.
comnrunicattons
usesihe HTTP
canalsostoreWebpagedatain othertypes
servers
\rVeti
to
protocol
comrnurrications
sucli
withtlreTCP/lP
conjunctiorr
Datastoredin databases,
of files,suchasdatabases.
{: is
A iriltli':l't'ii''i ;.1-i
for'
qetWebresollrces
to ir6tll"computer.
HTML
into
canbeassembled
asproductinformation,
a
document,
HTIML
as
an
such
A\A/eb
pagerequests'
anydatafilethathasa UP.L,
to \A/eb
mat"on thefly" in response
coirmands
includes
FITTP
file'
sound
or
a
data
irideo,
gets
the
a
it
when
data
curreni
clisplay
Eraphic,
pagecanalways
Vt/el:
with
con"lffiuTricate
ifrathelpbrowsers
or nretfrods
regularly'
thatisupdated
iroma database
flow
howthemessages
C-2illustrates
Figure
seilers.
I get a 4@4elroff what oloesthat rtmean?
c'somnretflrmes
:ii:iillr r; i I tlowlllleli
pages
gettcyoulcomputet
includes
to a browsertrequest
response
A Webserver's
'l
or notthe
whether
TlrollPl
intlrc
FGilo-'q;H..;"ffi;qini*eL'rr*
rri,detlratindicates
aniiJ'i:ill"li::iitr.is
il $Fr'/1;'$cqieardrr:lrl'llriri'"{?rj'rirtrril,&rlnL.rn*!dr!'il''
€.fu''
encounhave
AddfgSS
may
bfOWSgf'S
You
canbefulfilled.
request
browser's
the
boxcontains
thata browser
teredthe "404l\ot Found"message
ofthe
name
domain
suchasa Web
Webresource,
whena requested
thatYout
displays
\Neb
seruer
contacts.
codesare
browser
status
HTTP
page,doesnot exist.Common
in Table6-1.
sunrmarized
browser
2. Your
a socket
opens
to
andconnects
a s i m i l ioapr e n
at'the
socket
\AJeb
servet.
$aiuseodles
HTTF
i -'i:0ornmom
rflrr,l.,l:.
your
3. Next,
browser
generaies
anci
anHTTP
sends
message
ihe
through
Code
:lvlessage 'EescriPtiorl
301
\ /a5moved.
Theresource
N/oved
Permanenily
is'temPorarilY
Theresource
Ivioveci
TemporarilY unavailable.
303,
SeeOther
movedio another
Theresource
beautomaticallY
URL
andshould
bytheclientsof-tware.
retrieved
404
l\ot FounC
does
resource
Therequested
notexist.
-500
5eryer
Error
errof,such
server
Anunexpected
eno;
scriPiing
a
asencountering
occurred.
s0c(eI.
4. Theserver
the
back
sends
I-ITML
requested
ment
docu
'ihrough
ihe
open
sockets.
theresPonse,
sending
5. After
and
i'issocket
closes
theserver
itssocke'i.
closes
ihebrovvser
lfacl !i!ii:l