I-JavaScript: izibonelo isicelo

Uma kungenjalo ngokushesha ugxumele-syntax emfushane engasho lutho ukusebenza i-JavaScript, elula izibonelo ikhodi kuzosiza ukuze ufunde ngokushesha indlela yokuthuthukisa dynamism kanye nokwethulwa ngokuyiko kwezinhlelo emakhasini.

JS - ulimi lokwakha izinhlelo "ngaphakathi" lesiphequluli. I-JavaScript has olutheni ukusebenza zekhasi, izixazululo yokuqala emkhakheni lwezinhlelo into-ngamakhasimende, "uyakwazi" ukuxhumana neseva, ngoba abaningi ikhodi amasampula-JavaScript azitholakali ngokushesha siqonde futhi sisebenzise nezinye.

Jikelele ngokusebenzisa yangasese: isiqalo elula

UHlelo kusiphequluli namanje ngokulinganiswa ayemncane, kodwa zanqwabelana ngokushesha eliphezulu nesipiliyoni yasekuqaleni. I-syntax kanye engasho lutho we-JavaScript etholakele onesihloko esithi "okhokho", futhi enye ingxenye ukusebenza futhi iwusizo-syntax - kusukela pre-internet izinhlelo izilimi, ikakhulukazi C / C ++, Pascal.

Ukuphequlula nge-JavaScript izibonelo, musa ukufuna ukuba ngokushesha ukuqonda logic of ukucabanga labalobi kanye nokusebenza algorithm - lokhu umsebenzi unpromising, kangcono ukugxila siqu umkhuba yakho yangasese.

Mane nje uqale nge isibambi uxhumano ukufaka ku ithegi umzimba bese ubhala wendabuko "Sawubona" isitayela yesimanje "I`m ukulungele".

Lezi zibonelo zibonisa ku-JavaScript:

• umcimbi ukufaka, kwenzeka emva ukulayisha ikhasi inikwe isibambi - GoPage () umsebenzi;
• ilayisha ikhasi, nokuphatha umsebenzi uthola GoPage ();
• intercom umsebenzi aphapheme ulimi, elibonisa umlayezo isiphequluli "Sengilungele";
• isivakashi Browser ulindele ukuphendula.

Ehlaziya uchaza izenzo ngokuvamile kumele kwenziwe emva thwebula ikhasi bese uqala timer.

elula kakhulu: JS is kuxhumene kakhulu ngokungenakuhlukaniswa izakhi ikhasi. Ngakho, document.getElementById ucingo inikeza isixhumanisi div nge "scTimer" isihlonzi. Ukusebenzisa ukwakhiwa dTimer.innerHTML = "iyiphi esebenzayo ikhodi ye-HTML", ungakwazi ngamandla ukushintsha okuqukethwe div.

Kufanele ikakhulukazi sinake iphutha komzimba undesirability zokubhala ku-JavaScript. Izibonelo zalokhu kubangele emibi. Ikhodi ngenhla esibekiwe isaziso ( 'Ngikulungele'), futhi umsebenzi kungaqali. Ukuze akhombise yiluphi uhlobo lemigqa avunyelwe aphostrofi: kokubili single futhi double, lapho ngaphakathi bhangqa of fike hlobo ingase isetshenziselwe kuphela, omunye - njengoba iwuphawu.

Kulesi simo kufanele ziye esibekiwe, noma isaziso ( "Sengilungele"), isaziso ( 'I`m ukulungele'), isaziso ( 'Mina \' m ukulungele '), noma ezinye inhlanganisela.

Iphutha ku JS-ikhodi

Ekuqaleni kwaba isiphequluli, ekuthatheni isinyathelo isivakashi lapho ukulayishwa wesayithi, wakha esihlahleni se-DOM futhi amandla i-JavaScript umsebenzi: amnike ithuba sihlaziye ikhasi ezithwele, ukuqalisa izakhi zawo, umcimbi bokudla, bese uxhuma baxhumane iseva.

Ukuhlaziya i-JavaScript (izibonelo), kubalulekile ukuba banake ikhodi kungasebenzi. Le nqubo ngokuya ewela unjiniyela. Isiphequluli lapho umsebenzi wenziwa, yethule isiphakamiso lezi noma amanye amathuluzi okulungisa inkinga, kodwa okuhlangenwe nakho okubonisa ukuthi ukunamathela ngokuqinile syntax ulimi, akhululeke ukunemba algorithm nethonya elikhulu kakhulu ku ukuzuzwa imiphumela yokusebenza.