JavaScript: imizekelo isicelo

Ukuba akukho nangoko singene kwezivakalisi ngqo kunye semantics yokusebenza JavaScript, elula ikhowudi imizekelo kuya kukunceda ukufunda ngokukhawuleza ukuphucula indlela kakuhle uthsintsho kunye nocikizeko amaphepha.

JS - ulwimi lokuprograma "phakathi" browser. JavaScript unamava olunzulu esebenza iziqalelo page, izisombululo original kummandla senkqubo into ebomini, "uyakwazi 'ukunxibelelana kunye neseva, kuba abaninzi JavaScript khowudi iisampulu ayikho nangoko ziyafumaneka ukuqonda nokusebenzisa.

Jikelele phakathi zabucala: isiqalo elula

Programming kwi browser usemncinci kakhulu, kodwa ngokukhawuleza efunde ophezulu ezikumgangatho kunye namava yokuqala. Le kwezivakalisi kunye semantics ze JavaScript evela osihloko sithi "izinyanya", yaye inxalenye ukusebenza kunye usizo zombuzo - ukususela pre-intanethi ngeelwimi lwenkqubo, ingakumbi C / C ++, Pascal.

Ukhangelo imizekelo JavaScript, musa ukufuna ukuqonda nangoko ingqiqo yokucinga lwababhali kunye ukusebenza ubuchule - eli ingqesho, isenzakalo, kungcono ukuba banikel 'ingqalelo practice akho abucala.

Simply ukuqala nge Umqheba uqhagamshelo onload kwi tag lomzimba ukubhala "Molo" zemveli maxesha "I`m ukulungele".

Le mizekelo ibonisa ku JavaScript:

• umcimbi onload, kwenzeka emva ukulayisha ikhasi unikwe mphathi - GoPage () umsebenzi;
• layisha page, yaye umsebenzi ulawulo ifumana GoPage ();
• intercom umsebenzi yesilumkiso ulwimi, nto leyo ibonisa umyalezo kwi browser "Ndikulungele";
• Umkhangeli undwendwe ulindele yokusabela.

Ehlaziya ichaza izenzo ngokuqhelekileyo kufuneka wenziwe emva kokuba iphepha download kwaye Ukuqalisa isibali-xesha.

elula kakhulu: JS ngokusondeleyo kakhulu enxibelelene izinto page. Ngoko ke, document.getElementById umnxeba inikeza ikhonkco ukuya div with "scTimer" isazisi. Ukusebenzisa ulwakhiwo dTimer.innerHTML = "nayiphi na esebenzayo ikhowudi HTML", unako dynamically ukutshintsha imixholo div.

Kufuneka ngakumbi sinikele ingqalelo impazamo kumzimba undesirability kwezikripthi JavaScript. Imizekelo yoko iziphumo ezibi. Ikhowudi ngasentla elikhankanyiweyo kodityaniso ( 'Ndikulungele'), kunye nomsebenzi akanandaba. Ukuze ubonise naluphi na uhlobo imiqolo wavumela apostrophes: zombini abangatshatanga kabini, apho ngaphakathi iperi uhlobo omnye lungasetyenziswa kuphela, omnye - njengomfuziselo.

Kule meko kufuneka ukuba elikhankanyiweyo, nokuba qaphela ( "Ndikulungele"), tufwile ( 'I`m ukulungele'), tufwile ( 'I \' m ukulungele '), okanye ezinye ezihamba kunye.

Impazamo kwi JS-ikhowudi

Ekuqaleni yaba umkhangeli zincwadi, oko kulinyathelo undwendwe ke lolayisho iphepha le ndawo, wakha umthi DOM kwaye kwenziwe umsebenzi JavaScript: ukuba amnike ithuba ekuhlalutyeni iphepha ntli, qalisa izinto zayo, abaphatha isiganeko, uze uqhagamshele ukuba ziqhagamshelane kunye neseva.

Ukuhlaziya JavaScript (imizekelo), kuyimfuneko ukuba banikele ingqalelo ikhowudi kungasebenzi. Le nkqubo iba iwela umqambi. Umkhangeli apho umsebenzi wenziwa, isiphakamiso ezi okanye ezinye izixhobo edebugging, kodwa amava abonisa ukuba ukubambelela ngokungqongqo lo syntax ulwimi, ubulula ukuchaneka algorithm kuba nempembelelo enkulu kakhulu kufezekiso lweziphumo zokusebenza.