{"id":4310,"date":"2020-10-30T23:26:56","date_gmt":"2020-10-30T22:26:56","guid":{"rendered":"https:\/\/webhosting.de\/?p=4310"},"modified":"2020-10-30T23:26:56","modified_gmt":"2020-10-30T22:26:56","slug":"javascript","status":"publish","type":"post","link":"https:\/\/webhosting.de\/da\/javascript\/","title":{"rendered":"JavaScript"},"content":{"rendered":"<p>JavaScript er en af de tre store webhoteller: ud over <a href=\"https:\/\/webhosting.de\/da\/html-hypertext-markup-language\/\">HTML<\/a> (sidestruktur) og CSS (pr\u00e6sentation) tilbyder det objektorienterede programmeringssprog dynamisering af indholdet. Men JavaScript kan ikke kun anvendes i forbindelse med sidedesign. Server-side applikationer kan ogs\u00e5 styres med JavaScript.<\/p>\n<h2>Oprindelsen af JavaScript<\/h2>\n<p>P\u00e5 trods af navnet har JavaScript ikke meget med Java at g\u00f8re. Oprindeligt skulle scriptingsproget hedde LiveScript og blev udviklet af Netscape til interaktion mellem Netscape Navigator og Java-applets (Java-klientprogrammer). Som faktisk propriet\u00e6r software udgjorde JavaScript en konkurrencefaktor for virksomheder som f.eks. <a href=\"https:\/\/webhosting.de\/da\/emails-microsoft-werden-abgewiesen\/\">Microsoft<\/a> repr\u00e6senteret. De reagerede p\u00e5 udviklingen af JavaScript med deres egne l\u00f8sninger som f.eks. scriptingsproget JScript. Med tiden har JavaScript imidlertid etableret sig som det prim\u00e6re scriptingsprog, der nu underst\u00f8ttes af alle browsere, til klientside og (ud over <a href=\"https:\/\/webhosting.de\/da\/php\/\">php<\/a>) dynamisering p\u00e5 server-siden.<\/p>\n<h3>Dynamisering p\u00e5 klientsiden<\/h3>\n<p>Den mest anvendte funktion i JavaScript er nok muligheden for dynamisering p\u00e5 klientsiden. Klienten er webbrowseren. Dynamisering p\u00e5 klientsiden betyder, at det konkrete indhold, der vises i klienten, manipuleres. HTML er den statiske beskrivelse af strukturen p\u00e5 et websted, den s\u00e5kaldte Document Object Model (DOM). Mens CSS (Cascading Style Sheets) anvendes til separat udformning af dette \"skelet\", giver JavaScript mulighed for at flytte, slette eller tilf\u00f8je HTML-elementer.<\/p>\n<p>Denne DOM-manipulation (DOM-scripting) kan bruges p\u00e5 mange m\u00e5der. Funktioner er oprindeligt bundet til bestemte h\u00e6ndelser via s\u00e5kaldte event handlers. Det kan v\u00e6re brugerens klik, tidspunkter eller endda indl\u00e6sning af webstedet. Event-baserede \u00e6ndringer kan derefter udl\u00f8ses via de ID'er, der er tildelt elementer i HTML. Dette kan omfatte alt fra programmering af enkle, dynamiske formularer eller tabelfiltre til indlejring af videoafspillere eller kompleks, dynamisk grafik.<\/p>\n<h3>JQuery: Den mindre komplicerede JavaScript<\/h3>\n<p>JavaScript er et eksempel p\u00e5 objektorienterede programmeringssprog. Derfor er adgangst\u00e6rsklen for uerfarne webdesignere relativt h\u00f8j. Uden at begr\u00e6nse JavaScript-funktionerne (meget) tilbyder JavaScript-biblioteket JQuery en forenklet syntaks, der g\u00f8r det muligt at anvende de mest almindelige anvendelsesmuligheder p\u00e5 en hurtig og nem m\u00e5de. Mens JavaScript med sin definition af prototyper (i stedet for klasser), instanser (konkrete objekter) og metoder (funktioner, der er bundet til objekter) har samme kompleksitet og foranderlighed som f.eks. Java eller Python, begr\u00e6nser JQuery ordforr\u00e5det og strukturerne. Kommandoerne kan inds\u00e6ttes i hinanden, s\u00e5 strukturen kan forst\u00e5s ret hurtigt. Medmindre der er tale om komplekse, us\u00e6dvanlige applikationer, er det derfor meget sandsynligt, at der findes en enkel l\u00f8sning i JQuery.<\/p>\n<h3>Dynamisering p\u00e5 serversiden: AJAX og Node.js<\/h3>\n<p>Ud over DOM-manipulation bruges JavaScript ogs\u00e5 til kommunikation med servere, f.eks. til databaseforesp\u00f8rgsler. Siden 2009 har der v\u00e6ret node.js, en ramme for dynamisering p\u00e5 serversiden med JavaScript. Det var allerede muligt f\u00f8r 2009, men node.js g\u00f8r det nemmere at integrere det. Dette er en fordel for JavaScript-programm\u00f8rer, da de ikke l\u00e6ngere beh\u00f8ver at ty til andre sprog som f.eks. php. Desuden giver node.js ogs\u00e5 mulighed for parallelisering af processer. Det er en fordel, fordi for mange af disse s\u00e5kaldte tr\u00e5de kan f\u00f8re til stilstand. Med node.js k\u00f8rer anmodninger p\u00e5 en enkelt tr\u00e5d, hvilket kan \u00f8ge ydeevnen betydeligt.<\/p>\n<p>Node.js er et eksempel p\u00e5 de muligheder, som AJAX giver. Akronymet st\u00e5r for en procedure kaldet Asynchronous JavaScript and XML. Dette princip g\u00f8r det muligt at anmode om indhold fra servere uden at skulle genindl\u00e6se hele siden. For mange webtilbud som YouTube ville det v\u00e6re en stor ulempe at skulle genindl\u00e6se hele webstedet efter videoopkald eller indl\u00e6sning af kommentarer. AJAX er ogs\u00e5 en l\u00f8sning p\u00e5 problemet med ophobning af foresp\u00f8rgsler takket v\u00e6re asynkron behandling, som forklaret ovenfor for Node.js.<\/p>\n<h3>JavaScript-integration<\/h3>\n<p>Den grundl\u00e6ggende integration af JavaScript i webtilbud fungerer p\u00e5 n\u00f8jagtig samme m\u00e5de som forbindelsen med CSS-filer. Der er to muligheder for dette: P\u00e5 den ene side kan JavaScript bruges i hovedet og p\u00e5 den anden side i kroppen af HTML-dokumentet.<\/p>\n<p>&nbsp;<\/p>","protected":false},"excerpt":{"rendered":"<p>JavaScript geh\u00f6rt zu den gro\u00dfen drei des Webhostings: Neben HTML (Seitenstruktur) und CSS (Darstellung) bietet die objektorientierte Programmiersprache Dynamisierung von Inhalten. Aber JavaScript ist nicht nur im Kontext der Seitengestaltung einsetzbar. Auch serverseitige Anwendungen k\u00f6nnen mit JavaScript kontrolliert werden. Urspr\u00fcnge von JavaScript Trotz des Namens hat JavaScript nur wenig mit Java zu tun. Urspr\u00fcnglich sollte [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":936,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_crdt_document":"","inline_featured_image":false,"footnotes":""},"categories":[732],"tags":[335,336,337],"class_list":["post-4310","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-lexikon","tag-javascript","tag-jquery","tag-js"],"acf":[],"_wp_attached_file":null,"_wp_attachment_metadata":null,"litespeed-optimize-size":null,"litespeed-optimize-set":null,"_elementor_source_image_hash":null,"_wp_attachment_image_alt":null,"stockpack_author_name":null,"stockpack_author_url":null,"stockpack_provider":null,"stockpack_image_url":null,"stockpack_license":null,"stockpack_license_url":null,"stockpack_modification":null,"color":null,"original_id":null,"original_url":null,"original_link":null,"unsplash_location":null,"unsplash_sponsor":null,"unsplash_exif":null,"unsplash_attachment_metadata":null,"_elementor_is_screenshot":null,"surfer_file_name":null,"surfer_file_original_url":null,"envato_tk_source_kit":null,"envato_tk_source_index":null,"envato_tk_manifest":null,"envato_tk_folder_name":null,"envato_tk_builder":null,"envato_elements_download_event":null,"_menu_item_type":null,"_menu_item_menu_item_parent":null,"_menu_item_object_id":null,"_menu_item_object":null,"_menu_item_target":null,"_menu_item_classes":null,"_menu_item_xfn":null,"_menu_item_url":null,"_trp_menu_languages":null,"rank_math_primary_category":null,"rank_math_title":null,"inline_featured_image":null,"_yoast_wpseo_primary_category":null,"rank_math_schema_blogposting":null,"rank_math_schema_videoobject":null,"_oembed_049c719bc4a9f89deaead66a7da9fddc":null,"_oembed_time_049c719bc4a9f89deaead66a7da9fddc":null,"_yoast_wpseo_focuskw":"javascript","_yoast_wpseo_linkdex":null,"_oembed_27e3473bf8bec795fbeb3a9d38489348":null,"_oembed_c3b0f6959478faf92a1f343d8f96b19e":null,"_trp_translated_slug_en_us":null,"_wp_desired_post_slug":null,"_yoast_wpseo_title":null,"tldname":null,"tldpreis":null,"tldrubrik":null,"tldpolicylink":null,"tldsize":null,"tldregistrierungsdauer":null,"tldtransfer":null,"tldwhoisprivacy":null,"tldregistrarchange":null,"tldregistrantchange":null,"tldwhoisupdate":null,"tldnameserverupdate":null,"tlddeletesofort":null,"tlddeleteexpire":null,"tldumlaute":null,"tldrestore":null,"tldsubcategory":null,"tldbildname":null,"tldbildurl":null,"tldclean":null,"tldcategory":null,"tldpolicy":null,"tldbesonderheiten":null,"tld_bedeutung":null,"_oembed_d167040d816d8f94c072940c8009f5f8":null,"_oembed_b0a0fa59ef14f8870da2c63f2027d064":null,"_oembed_4792fa4dfb2a8f09ab950a73b7f313ba":null,"_oembed_33ceb1fe54a8ab775d9410abf699878d":null,"_oembed_fd7014d14d919b45ec004937c0db9335":null,"_oembed_21a029d076783ec3e8042698c351bd7e":null,"_oembed_be5ea8a0c7b18e658f08cc571a909452":null,"_oembed_a9ca7a298b19f9b48ec5914e010294d2":null,"_oembed_f8db6b27d08a2bb1f920e7647808899a":null,"_oembed_168ebde5096e77d8a89326519af9e022":null,"_oembed_cdb76f1b345b42743edfe25481b6f98f":null,"_oembed_87b0613611ae54e86e8864265404b0a1":null,"_oembed_27aa0e5cf3f1bb4bc416a4641a5ac273":null,"_oembed_time_27aa0e5cf3f1bb4bc416a4641a5ac273":null,"_tldname":null,"_tldclean":null,"_tldpreis":null,"_tldcategory":null,"_tldsubcategory":null,"_tldpolicy":null,"_tldpolicylink":null,"_tldsize":null,"_tldregistrierungsdauer":null,"_tldtransfer":null,"_tldwhoisprivacy":null,"_tldregistrarchange":null,"_tldregistrantchange":null,"_tldwhoisupdate":null,"_tldnameserverupdate":null,"_tlddeletesofort":null,"_tlddeleteexpire":null,"_tldumlaute":null,"_tldrestore":null,"_tldbildname":null,"_tldbildurl":null,"_tld_bedeutung":null,"_tldbesonderheiten":null,"_oembed_ad96e4112edb9f8ffa35731d4098bc6b":null,"_oembed_8357e2b8a2575c74ed5978f262a10126":null,"_oembed_3d5fea5103dd0d22ec5d6a33eff7f863":null,"_eael_widget_elements":null,"_oembed_0d8a206f09633e3d62b95a15a4dd0487":null,"_oembed_time_0d8a206f09633e3d62b95a15a4dd0487":null,"_aioseo_description":null,"_eb_attr":null,"_eb_data_table":null,"_oembed_819a879e7da16dd629cfd15a97334c8a":null,"_oembed_time_819a879e7da16dd629cfd15a97334c8a":null,"_acf_changed":null,"_wpcode_auto_insert":null,"_edit_last":null,"_edit_lock":null,"_oembed_e7b913c6c84084ed9702cb4feb012ddd":null,"_oembed_bfde9e10f59a17b85fc8917fa7edf782":null,"_oembed_time_bfde9e10f59a17b85fc8917fa7edf782":null,"_oembed_03514b67990db061d7c4672de26dc514":null,"_oembed_time_03514b67990db061d7c4672de26dc514":null,"rank_math_news_sitemap_robots":"index","rank_math_robots":["index"],"_eael_post_view_count":"4035","_trp_automatically_translated_slug_ru_ru":null,"_trp_automatically_translated_slug_et":"javascript","_trp_automatically_translated_slug_lv":"javascript","_trp_automatically_translated_slug_fr_fr":null,"_trp_automatically_translated_slug_en_us":null,"_wp_old_slug":null,"_trp_automatically_translated_slug_da_dk":null,"_trp_automatically_translated_slug_pl_pl":null,"_trp_automatically_translated_slug_es_es":null,"_trp_automatically_translated_slug_hu_hu":null,"_trp_automatically_translated_slug_fi":"javascript","_trp_automatically_translated_slug_ja":"%e3%82%b8%e3%83%a3%e3%83%90%e3%82%b9%e3%82%af%e3%83%aa%e3%83%97%e3%83%88","_trp_automatically_translated_slug_lt_lt":null,"_elementor_edit_mode":null,"_elementor_template_type":null,"_elementor_version":null,"_elementor_pro_version":null,"_wp_page_template":"default","_elementor_page_settings":null,"_elementor_data":null,"_elementor_css":null,"_elementor_conditions":null,"_happyaddons_elements_cache":null,"_oembed_75446120c39305f0da0ccd147f6de9cb":null,"_oembed_time_75446120c39305f0da0ccd147f6de9cb":null,"_oembed_3efb2c3e76a18143e7207993a2a6939a":null,"_oembed_time_3efb2c3e76a18143e7207993a2a6939a":null,"_oembed_59808117857ddf57e478a31d79f76e4d":null,"_oembed_time_59808117857ddf57e478a31d79f76e4d":null,"_oembed_965c5b49aa8d22ce37dfb3bde0268600":null,"_oembed_time_965c5b49aa8d22ce37dfb3bde0268600":null,"_oembed_81002f7ee3604f645db4ebcfd1912acf":null,"_oembed_time_81002f7ee3604f645db4ebcfd1912acf":null,"_elementor_screenshot":null,"_oembed_7ea3429961cf98fa85da9747683af827":null,"_oembed_time_7ea3429961cf98fa85da9747683af827":null,"_elementor_controls_usage":null,"_elementor_page_assets":[],"_elementor_screenshot_failed":null,"theplus_transient_widgets":["tp-video-player"],"_eael_custom_js":null,"_wp_old_date":null,"_trp_automatically_translated_slug_it_it":null,"_trp_automatically_translated_slug_pt_pt":null,"_trp_automatically_translated_slug_zh_cn":null,"_trp_automatically_translated_slug_nl_nl":null,"_trp_automatically_translated_slug_pt_br":null,"_trp_automatically_translated_slug_sv_se":null,"rank_math_analytic_object_id":"716","rank_math_internal_links_processed":null,"_trp_automatically_translated_slug_ro_ro":null,"_trp_automatically_translated_slug_sk_sk":null,"_trp_automatically_translated_slug_bg_bg":null,"_trp_automatically_translated_slug_sl_si":null,"litespeed_vpi_list":["webhostinglogo.png"],"litespeed_vpi_list_mobile":["webhostinglogo.png"],"rank_math_seo_score":null,"rank_math_contentai_score":null,"ilj_limitincominglinks":null,"ilj_maxincominglinks":null,"ilj_limitoutgoinglinks":null,"ilj_maxoutgoinglinks":null,"ilj_limitlinksperparagraph":null,"ilj_linksperparagraph":null,"ilj_blacklistdefinition":null,"ilj_linkdefinition":["javascript"],"_eb_reusable_block_ids":null,"rank_math_focus_keyword":"javascript","rank_math_og_content_image":null,"_yoast_wpseo_metadesc":"JavaScript geh\u00f6rt zu den gro\u00dfen drei des Webhosting. Trotz des Namens hat JavaScript nur wenig mit Java zu tun.","_yoast_wpseo_content_score":null,"_yoast_wpseo_focuskeywords":null,"_yoast_wpseo_keywordsynonyms":null,"_yoast_wpseo_estimated-reading-time-minutes":null,"rank_math_description":"JavaScript geh\u00f6rt zu den gro\u00dfen drei des Webhosting. Trotz des Namens hat JavaScript nur wenig mit Java zu tun.","surfer_last_post_update":null,"surfer_last_post_update_direction":null,"surfer_keywords":null,"surfer_location":null,"surfer_draft_id":null,"surfer_permalink_hash":null,"surfer_scrape_ready":null,"_thumbnail_id":"936","footnotes":null,"_links":{"self":[{"href":"https:\/\/webhosting.de\/da\/wp-json\/wp\/v2\/posts\/4310","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/webhosting.de\/da\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/webhosting.de\/da\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/webhosting.de\/da\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/webhosting.de\/da\/wp-json\/wp\/v2\/comments?post=4310"}],"version-history":[{"count":0,"href":"https:\/\/webhosting.de\/da\/wp-json\/wp\/v2\/posts\/4310\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/webhosting.de\/da\/wp-json\/wp\/v2\/media\/936"}],"wp:attachment":[{"href":"https:\/\/webhosting.de\/da\/wp-json\/wp\/v2\/media?parent=4310"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/webhosting.de\/da\/wp-json\/wp\/v2\/categories?post=4310"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/webhosting.de\/da\/wp-json\/wp\/v2\/tags?post=4310"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}