{"id":1207,"date":"2020-02-03T21:17:36","date_gmt":"2020-02-03T20:17:36","guid":{"rendered":"https:\/\/maxfest.dk\/port\/?p=1207"},"modified":"2020-02-04T11:32:17","modified_gmt":"2020-02-04T10:32:17","slug":"noter-javascript","status":"publish","type":"post","link":"https:\/\/maxfest.dk\/port\/skiftligt-materiale\/noter\/noter-javascript\/","title":{"rendered":"Noter: JavaScript"},"content":{"rendered":"\n

Noter om JavaScript taget p\u00e5 UCL.<\/p>\n\n\n\n

Om JavaScript<\/h2>\n\n\n\n

Javascript er et clientside script sprog (en type kodesprog). Dvs. at koden eksekverer hos brugeren. Javascript kan bruges i mange browsere, og i nyere tid i stort set alle moderne browsere. Man b\u00f8r dog v\u00e6re opm\u00e6rksom p\u00e5 at brugere kan sl\u00e5 det fra.<\/p>\n\n\n\n

Javascript blev opfundet af NetScape i 1995, som del af Netscape Navigator (browser) og blev lanceret 1996. Javascript f\u00f8lger en standard kaldet ECMA. Den seneste der f\u00f8lges er ECMA Script 5.<\/p>\n\n\n\n

Javascript bruges til at processere indhold hos klienten. N\u00e5r Javascript \u00e6ndrer HTML kaldes det DOM scripting.<\/p>\n\n\n\n

Test og fejlfinding af JavaScript<\/h2>\n\n\n\n

Javascript stopper med at virke hvis der st\u00f8des p\u00e5 fejl i scriptet. Derfor er det en god id\u00e9 at \u00e5bne konsollen i browseren man arbejder i, for at se eventuelle fejl. I de fleste browsere kan man trykke p\u00e5 f12 for at \u00e5bne udvikler panelet. Tryk derefter p\u00e5 console. I console kan man ogs\u00e5 skrive javascript for at k\u00f8re det i sessionen.<\/p>\n\n\n\n

Ikluder JavaScript<\/h2>\n\n\n\n

Javascript kan skrives mellem script tags og linkes til i et script tag.<\/p>\n\n\n\n

<!-- example 1 -->\n<script scr=\"javascript-file.js\"><\/script>\n<!-- example 2 -->\n<script>\n\/\/ JavaScript code here\n<\/script><\/code><\/pre>\n\n\n\n
Scripts kan inkluderes i head og body.<\/p>\n\n\n\n
 Syntax<\/h2>\n\n\n\n
JavaScript er case sensitive.<\/p>\n\n\n\n
JavaScript kode sluttes af med semikolon (;).<\/p>\n\n\n\n
JavaScript ignorerer whitespace.<\/p>\n\n\n\n
JavaScript variabler<\/h3>\n\n\n\n
En defineret v\u00e6rdi.<\/p>\n\n\n\n
Eksempler:<\/p>\n\n\n\n
var variabel = \"value\";\nvar number = 1;\nvar boolean = true;\nvar otherBoolean = false;\nvar notANumber = NaN;\nvar isNull = null;<\/code><\/pre>\n\n\n\n
Metode<\/h2>\n\n\n\n
Ved at anvende defer kan man skubbe udf\u00f8relsen af Javascript til efter at HTML er blevet indl\u00e6st.<\/p>\n\n\n\n
Eksempel:<\/p>\n\n\n\n
<script src=\"example.js\" defer><\/script><\/code><\/pre>\n\n\n\n
Tips<\/h3>\n\n\n\n
  • Skriv CamelCase<\/li>
  • Forbedre l\u00e6sbarhed af kode med whitespace.<\/li>
  • Afslut alle statements med semicolon.<\/li>
  • Kommenter kode ofte.<\/li><\/ul>\n\n\n\n
    Skriv kommentarer<\/h3>\n\n\n\n
    Man kan udkommentere en linje kode efter “\/\/”.<\/p>\n\n\n\n
    Man kan udkommentere alt indhold mellem “\/*” og “*\/”.<\/p>\n\n\n\n
    Eksempler:<\/p>\n\n\n\n
    <script>\n\/\/ Hidden code\n\/* Hidden code *\/\n<\/script><\/code><\/pre>\n\n\n\n
    <\/p>\n","protected":false},"excerpt":{"rendered":"
    Noter om JavaScript taget p\u00e5 UCL. Om JavaScript Javascript er et clientside script sprog (en type kodesprog). Dvs. at koden eksekverer hos brugeren. Javascript kan bruges i mange browsere, og i nyere tid i stort set alle moderne browsere. Man b\u00f8r dog v\u00e6re opm\u00e6rksom p\u00e5 at brugere kan sl\u00e5 det fra. Javascript blev opfundet af…<\/p>\n","protected":false},"author":1,"featured_media":715,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[11],"tags":[18],"class_list":["post-1207","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-noter","tag-mmd"],"_links":{"self":[{"href":"https:\/\/maxfest.dk\/port\/wp-json\/wp\/v2\/posts\/1207","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/maxfest.dk\/port\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/maxfest.dk\/port\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/maxfest.dk\/port\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/maxfest.dk\/port\/wp-json\/wp\/v2\/comments?post=1207"}],"version-history":[{"count":9,"href":"https:\/\/maxfest.dk\/port\/wp-json\/wp\/v2\/posts\/1207\/revisions"}],"predecessor-version":[{"id":1218,"href":"https:\/\/maxfest.dk\/port\/wp-json\/wp\/v2\/posts\/1207\/revisions\/1218"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/maxfest.dk\/port\/wp-json\/wp\/v2\/media\/715"}],"wp:attachment":[{"href":"https:\/\/maxfest.dk\/port\/wp-json\/wp\/v2\/media?parent=1207"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/maxfest.dk\/port\/wp-json\/wp\/v2\/categories?post=1207"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/maxfest.dk\/port\/wp-json\/wp\/v2\/tags?post=1207"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}