I-JavaScript loops, ngokuba kuyilapho, do-ngenkathi

Umlando kumiswa yesimanje ulimi lokwakha-syntax iyafana inqubo ulwazi yonke. Futhi ukuthi kwakunjalo ekuqaleni ... Kodwa manje yonke into ilula futhi okungabizi.

I-algorithm ekugcineni - njalo neketanga Daisy imiyalo. Impindamqondo izinhlelo - setha uma ukulandelanisa kuhlanganiswe. Round-robin wayengalokothi ezingokoqobo ukuze serial noma parallel umyalo chain. Amalebula, ukuhwebelana, kanye nemibandela - nje ngokwanele nganoma yisiphi isixazululo. izilimi Functional baye bancishwa ukubaluleka kwalezi imibono, kodwa isidingo ukuphinda izigaba ikhodi wahlala.

Isiphequluli se-DOM, ulimi lwakhe + iseva

Esine-imijikelezo ahlale, nakuba imibono obusebenzayo atholwe nencazelo ekhethekile. Mhlawumbe okuthile osele "ukufefeza" futhi "wesisusa", kodwa ngaphezu kwakho konke, endaweni lapho JavaScript uhlala, okwaholela yokuthi kukhona, kodwa kuyangabazeka ukuthi lesi sinqumo yakamuva.

I-JavaScript eyehlayo ngaphakathi isiphequluli uthola ikhasi, parses kube DOM futhi iqala iskripthi kuqala. Wonke amakhasi nezinye, kuhlanganise ukulandwa kule - kuba unjiniyela izandla balawula ulimi lapho khodi iseva bese imiphumela usebenzisa izinhlelo ze-AJAX indlela kungenziwa Lusetshenziswa.

Isiphequluli wenza ukuthola esine-ikhodi bangasebenzisa izinto isiphequluli, kuhlanganise omunye okuhambisa idatha ku-server futhi ithole impendulo, njengokuthi imaphi ingaba njengesihluthulelo i HTML-yomdwebo nezitayela futhi ikhodi yangempela. Impendulo ingase emelelwa afanayo kanye netintfo. Sense ukusebenzisa i-JavaScript imijikelezo elahlekile, amathuba yavama ukwenza ngaphandle kwabo, futhi kokubanga isiphequluli hang kulandzelana esingapheliyo imiyalo akulona ikhambi best.

Empeleni izihibe zikhona iningi JavaScript-syntax, onjiniyela bangaphatha umphelelisi design ejwayelekile imisebenzi yabo.

I-JavaScript ikhodi isikhundla emkhathini

uMklami Modern akusho ngisho bacabange ukuthi wayevamile umjikelezo (ngoba, I ngenkathi, do I ngenkathi, ...) - ekupheleni uchungechunge imijikelezo (nowe) processor, ukulandelana okulula imisebenzi kanambambili, ophazamisekile ekuphumeni zokubala, okusho izimo.

Ngenxa yalokho, lo mjikelezo akuyona ezingeni umshini Ulimi: luyinhlanganisela imiyalo evamile, imisebenzi okunemibandela nezinguquko. Khuphuka kuleveli, kungakhathaliseki ukuthi izindlela lingasetshenziswa sokuthuthukiswa isiphequluli kanye ne-JavaScript Interpreter, imijikelezo kuyoba esiyingqayizivele. Futhi "izingcezu ikhodi" izokwethulwa ezikhathini ezahlukene kanye nezizukulwane ezahlukene program. Phansi engenhla "ekwakheni»-JavaScript. I-syntax alinikela yesimanje-JavaScript imijikelezo.

JS - Ulimi enhle: esisebenzayo, zanamuhla futhi iyavela-full. I-syntax lo mshini kuhlanganisa wonke kwaqanjwa abadlule evelile futhi babe isisekelo iyiphi algorithm ezingeguquleke. Kodwa ngoba imijikelezo uma kunesidingo, ngempela? Intuthuko izinhlelo ngizibuze imibuzo bemvelo ayisisekelo, kodwa kwezinye izimo, ukuthola isixazululo.

ngezizathu inhloso

Umjikelezo kungenzeka ezimbili kuphela okuhlukile isimo noma counter, kodwa eqinisweni (ezingeni aphansi) iyiphi umjikelezo - kuphela nje osekelwe. Kwezinye izilimi umjikelezo ezivamile "ngayinye." Ngo-JavaScript imijikelezo foreach isakhiwo emelelwa esi entweni, kodwa kungenzeka ukusebenzisa array.forEach okufana (...).

Kunoma ikuphi, ezimbili okufanele akhethe kuzo: ikhodi emshinini engikhiphela ekugcineni zonke algorithm uHlelo, ngisho ubhala ku izilimi ehumusha, ayinakho ezinye izinketho umyalo uchungechunge uphinda: abe into ukwenza futhi kuze kube:

• esiphikisayo ibala;
• kuze kube isimo uhlangana.

I-JavaScript - a umhumushi ejwayelekile. Sici Its ehlukile: esebenza ngaphakathi isiphequluli isebenzisa izinhloso zawo ikuvumela ukuba enze ubuchule ohlangothini iklayenti sesilayishile lelikhasi esipheqululini, futhi ngokuhamba umsebenzi walo.

umjikelezo Simple ngamunye

On JavaScript foreach izihibe ibukeke ukusetshenziswa imisebenzi amalungu afanayo:

Ukusetshenziswa imijikelezo enjalo musa okungadala ubunzima. Ngokusemthethweni, akukho umjikelezo langempela. Kukhona uhambisane ukwelashwa umsebenzi izici afanayo.

Cycle ekhawunteni

Okuningi ejwayele ukubheka i-JavaScript imijikelezo ngoba:

Lapha, counter wenza variable ogama value buyahluka kuye ngezinkathi ifomula futhi uphawu uyisiphetho isimo umjikelezo. Akunjalo ngempela formula futhi isimo kuhlanganisa umjikelezo onhlobonhlobo. Kodwa ukulawula iphuzu ekupheleni emjikelezweni kunqunywa ngokuphelele okuqukethwe kwabo.

izihibe okunemibandela

Inketho nge ngenkathi i-JavaScript inikeza, kuye ngokuthi lapho udinga ukuhlola isimo. Uma umzimba loop angeke ibulawe ngisho nakanye - lena, uma umzimba okufanele kwenziwe okungenani esisodwa, kuba enye into:

Esimweni sokuqala, nokuchaza ngenkathi design, i-JavaScript lokuqala ihlola isimo, futhi uma lokhu kuyiqiniso, engikhiphela loop. Esimeni sesibili umjikelezo eziyokhishwa kuqala. Uma umphumela eziguquguqukayo elicacisiwe ezakhiwe enikeziwe ngesikhathi, kuzothatha ukubaluleka amanga, loop sithule.

inhlanganisela ezinkulu algorithm elula

Umsebenzi oyinhloko (ebalulekile okuyingxenye) wanoma iyiphi algorithm - ukuthola, bese kuphela wenze isinqumo mayelana yini okufanele uyenze ngokulandelayo. I bakudala kunazo search option - isikhalo kwenombolo, umphumela uba ngokushesha. Uma eziguquguqukayo eziningi, futhi inamanani amaningi (ilungu elifanayo), khona-ke amagugu isampula kumele batholwe ezinquma ukuthi liyobe linjani ukuziphatha ikusasa iskripthi.

Le mfundiso alula enziwe iluphu nge counter e-JavaScript ulimi uhlobo panacea for zonke izinkinga. amakhompyutha Modern isivinini ezahlukene. Isikhathi amaskriphthi ku ngokwanele isiphequluli, akukho ezisheshayo. Kulula sokulungisa into okuthile. Ngenxa yalokho, J avaScript ngoba izihibe zithandwa kakhulu.

Engalungile nge lolu hlobo lutho. Kodwa ngemva kwale ndlela kulula ukulahlekelwa okushiwo okuyiwona elilodwa noma kwenye algorithm ebhaliwe. Lezi akuzona okungenanzuzo. Konke okulotshiwe, yiluphi uhlelo eyenza umqondo. yokudla ngokweqile ngezinye J avaScript imijikelezo ngoba, unjiniyela abakwazi ukubona okushiwo ilungelo hhayi ukudala i-algorithm ezanele.

Ukusebenza, omunye umfanekiso wanoma ngokoqobo

однотипного кода можно представить функциями - алгоритм сразу преобразится, основное тело скрипта уменьшится в размере, все станет читаемым и понятным. Ukusebenzisa i-JavaScript-imijikelezo, izibonelo uhlobo olufanayo ikhodi zingamelela imisebenzi - algorithm kanye siguqulwe, umzimba omkhulu iskripthi encishisiwe ngobukhulu, konke kuyoba esifundekayo futhi kuyaqondakala.

Leli akulona ikhambi ngokuphelele entsha, kodwa empeleni akusiyo awanakufundwa nezinye kwaqanjwa ulimi. Ikakhulukazi, J avaScript imijikelezo ingatholakala yokuhlukanisa classical () umsebenzi:

cResult = '9,8,7,6,5,4' ; var cResult = '9,8,7,6,5,4';
aResult = cResult . var aResult = cResult. ( ',' ); yokuhlukanisa ( ',');

Akukho umjikelezo, kodwa ngenye indlela okwenziwa lo msebenzi, uma hhayi ngifuna uphawu '' futhi ulisebenzise ukuhlukanisa inombolo eyodwa ukusuka kwenye.

Abstracting kusukela kanjani luyasetshenziswa ngaphakathi yokwahlukana () umsebenzi kungenziwa kulekelelwa-JavaScript yayo ukusebenza usebenzisa imijikelezo ngokuya ukusetshenziswa - elula kakhudlwana. Kusemqoka ukuthi le ndlela kuholela ukuthuthukiswa ukusebenza umsebenzi ngamunye, ngokulandelana, kodwa inani namanje ukuba le ndlela.

Lezi imisebenzi allt (), padc (), padl () futhi padr () - lokho akekho ku-JavaScript, kodwa ngezinye izikhathi kuyadingeka ukuze ususe kusukela yezinhlamvu noma izikhala ukuze uqondanise ubude string kwesobunxele, kwesokudla noma zombili. NgoLwesine kutholakale isidumbu sendoda le misebenzi - esine-imijikelezo. Simple, kufinyeleleke futhi ungalokothi hang algorithm esebenzisa ke.

Embodiments inombolo ukuguqulwa nemisebenzi 16-lekile ukubala 10-th futhi emuva ohlelweni, kuba lula ukutshela idatha kusuka komunye format kwesinye, kwakheka lapha ngumuntu do ngenkathi imijikelezo. -syntax icwecwe kakhulu futhi ephumelelayo.

Imijikelezo Lungisa - ukumelwa engokoqobo

I-JavaScript - ungathandi nezinye izilimi izinhlelo kanye ezihlukahlukene ezahlukene izinguqulo, futhi okubaluleke kakhulu, ivame ukuba ushintshe syntax nokwenza futhi usinwebise.

Unicode ukucabanga usebenzisa JS futhi uhluke PHP uMklami ukucabanga (ngokukhethekile, nezinye izilimi isiyonke, kahle, ngaphandle ukuthi "wesisusa 'wathi abalandeli bakhe akufakiwe ohlangothini jikelele), lapho i-algorithm akugcini eziguquguqukayo, afanayo, isabelo opharetha, izakhiwo eyindilinga .

Uma sicabange ukuthi azikho imijikelezo, futhi ukuxazulula le nkinga kubalulekile, kuyindlela elula (kuso) - zisikisela ukuthi uhlelo idatha, okuyizinto iphuzu noma amaphuzu uhlelo esikhaleni ulwazi. Liyini iphuzu futhi yini uhlelo amaphuzu - kuba isihloko sendawo ethile. Ukuze uhlelo, lo mqondo kusho: elula, lena iqoqo idatha elula. Njengoba ungacabanga, lokhu elula iqophelo elilodwa ezingeni ngezansi uhlelo kuyoba, kodwa ezingeni eliphakeme - iphuzu.

Nale ndlela, iphuzu ukunakekelwa - ukukhombisa ubuntu babo ngokusebenzisa izindlela zabo. Lapho iphuzu kule super-uhlelo, umsebenzi kohlelo - ukukhombisa essence yayo njengoba inhlanganisela izinhlangano okuqondene amaphuzu wakhe.

Le ndlela endala njengeBhayibheli ingasiza umqondo izilimi izinhlelo, kodwa namanje uye ayitholakalanga ukubonakaliswa kwayo ezanele izinhlelo. program abaningi bacabanga ngendlela efanele, kodwa umphumela umsebenzi wabo kushiya okuningi okufanele oyifunayo.

Kuyasiza ngezinye izikhathi ukugqoka ngebhandeshi emehlweni akhe ukubona izwe!