Phambi CSS - yokuqala, ukhululekile, practical

Usinga-elements kunye pseudo-kwiiklasi CSS: phambi, emva, hambisa, esebenzayo, njl - ithuba ngempumelelo ukuphucula umgangatho kwaye lula isiza kubulawa, hayi kuquka JavaScript-Umqheba ikhowudi kwi ezicacileyo, musa ifuna ezintsonkothileyo uyilo reaction, iziganeko izinto, iingxoxo kunye nezenzo umtyeleli.

Usinga elula, ezijongene nemiba ngemiba yezemfundo, kufuneka iipropati ukhetho ebalulekileyo ezininzi nangeepani copyright ezilula kunye nezintsonkothileyo: indlela yokuqala ukutsala ingqalelo, ngaphandle kweziphazamiso ukucacisa amanyathelo afunekayo ukuze uthsuphe wokuba endaweni eyiyo.

amathuba Great vula url xa elikhankanyiweyo () kwi imixholo pseudo. Eneneni, olu khetho ivula imimango ezintsha, zombini ngokwemiqathango download nantoni na iphepha, kunye ukusebenza kunokwenzeka nantoni naphi na

A isici esasenza pseudo

Usinga (:: phambi CSS, :: emva) yahlukile sezulu, selectors kunye pseudo-izigaba akazange ekuqaleni ezikhoyo emthini kuxwebhu. Mhlawumbi, xa kusenziwa kubaluleke kakhulu, kodwa ke xa sicinga umbuzo bakhawuleze Umxholo kwisiza, uthembe impahla umxholo into enenjongo ngexesha injini yokukhangela akwenzi ngqiqo.

Usinga :: kokuba CSS ikuvumela ukuba yongeza isiqulatho ukuya element, kwaye :: emva - emva. Iziqulatho ingahluka itekisi elula ukuya ukufometha entsonkothileyo ngokubhekiselele kwiipropati CSS, kodwa akukho tag HTML. Usinga kungenziwa ngokugqibeleleyo ibekwe ngaphakathi element, encamathele, kuba intsingiselo phambi nasemva lilinganiselwe neselula. Awunako nje ukucacisa sikhundla, kodwa ubukhulu, imibala, neemvelaphi, iifonti, kwaye usebenzise ezinye iimpawu CSS.

Njengoko Usinga le CSS, ngaphambi nasemva basuke beqale ngolu phawu ":", kodwa umgangatho CSS3 ekucetyiswa "::". Ukuhlola ukusetyenziswa ethile kwiphepha soze kuba ngaphezu kwezinye iibrawuza okanye kwiinguqulelo nje unakho uqaphele pseudo ethile.

Imiqathango jikelele yokusebenzisa

Ngokubeka, umz, div element echaza iklasi = 'scElement' kunye nomxholo "Isiqalelo" kwiphepha, nokwalatha inkcazelo yekhasi CSS-style:

.scElement {
POSITION ...;
z-indeksi ...;
...

}

ungafaka isicelo i pseudo ": hambisa" pseudo kunye ':: phambi "CSS:

.scElement: hambisa :: phambi {isiqulatho: 'isimaphambili'; umbala ...; imvelaphi-umbala ...;}.

Ngoko xa uhambisa i wesalathisi se mouse phambi ilizwi 'Isiqalelo' iya kuvela ilizwi 'isimaphambili', nto leyo eya ukutshintsha umbala oonobumba kunye nemvelaphi.

ukwahluka Content pseudo

Ukuba awukhankanyi iipropati pseudo, baya kuba iyafana naleyo i element engundoqo - scElement. Unga khankanya i url; kwandule ke impahla Umxholo: url ( '/ scBox / u-V / SC-rights.png') xa isalathisi ibonisa umfanekiso kwi element. Kwimeko Umxholo: "\ 03B1" livela ezibalo uphawu "alfa", kodwa asebenzise ababasebenzisi: "& nbsp;", " & lt;", "& laquo;", "& raquo;" kunye nabanye musa - ziya kuboniswa njengoko anjalo.

Wavumela oluninzi iinketho ukucacisa ikhontenti pseudo-: "umbhalo" eqhelekileyo, url (), ukulandelelana nabalinganiswa njengokom, yiya ku: vula-quote / close-quote, okanye akukho-open-quote / no-close-quote, njl Njengoko kuba kubonisa indawo olungagungqiyo umxholo. ngokusebenzisa iipropati isimbo, ngokusebenzisa ngaphambili, CSS izakubeka pseudo naphi na Ulutho elidityaniswe kuyo.

Unakho ukudibanisa ukusetyenziswa ngaxeshanye ngaphambili nasemva. Ngoko ke, ebeka usebenzisa CSS phambi abalinganiswa umxholo, ungafumana iintlobo yeziphumo, edibanisa ezahlukeneyo pseudo-iiklasi kunye pseudo-elements, kusimangalise undwendwe, imali ngexesha efanayo enye byte-ikhowudi JavaScript.

features pseudo

Kuba Amagama abo bamkela ":" ubuntu, kwakunye libhekisela pseudo, kodwa ngokungafani CSS3 kasinga ngokuqhelekileyo zibonakaliswe yi "::". Iibrawuza ukuze uqonde oko, ndiyaqonda zombini abizwa. Izikhewu ukurekhoda akuvumelekanga, umtya irekhodwe kunye pseudo (okanye kuphela) pseudo abhalwe kunye:

scElement: hambisa :: phambi {isiqulatho: 'isimaphambili'; ...}

scElement: esebenzayo: emva {Umxholo: 'suffix'; ...}

Kubalulekile ukuba ukhumbule: CSS phambi kokusebenza ngaphandle umxholo we sayithi. IziTayile akadibananga umxholo wephepha. Pseudo - akukho ngaphandle. Abayi kuvela emthini DOM nengathandekiyo ukuba bazisebenzise amacandelo afanelekileyo kwisiza - kokuqulathwe, abayi kufumana.

Ukusebenzisa i "" yaye "::" ixhaswa kumaqonga mobile kunye kubakhangeli zincwadi abasetyenziswayo, kodwa khangela umsebenzi iinguqulelo abadala badla kodwa akufuneki.

Umxholo we pseudo-ezingafakwanga umxholo weli nxuwa. Uya kubona iinjini zokuphendla. Indlela yokusebenzisa le imeko - kuxhomekeke kwimeko ethile, kodwa ke ubukho bokusetyenziswa CSS ngaphambili, kwakunye emva, ngokuzimeleyo okanye ezintsonkothileyo, umdla xa umxholo kukho url (). ukusetyenziswa ngqo i pseudo umxholo namakhonkco kwisiza, uya kumvumela ukuba ukukhuphela ifayile, umzekelo, umfanekiso.

Ukubanako ABAZITSHINTSHI iifayili isimbo intanethi (iifayile Uhlobo lwamakhasi ayingxangxasi - kungekho ngaphandle) akuyiphazamisi ifomu kwaye usebenzise pseudo njengoko iluncedo nangaliphi na ixesha, endaweni algorithm ekunene, kuxhomekeke izenzo umtyeleli lowo.