<\/span><\/h2>\n\n\n\nM\u1ed9t ng\u00f4n ng\u1eef m\u00e1y t\u00ednh l\u00e0 danh s\u00e1ch c\u00e1c h\u01b0\u1edbng d\u1eabn \u0111\u01b0\u1ee3c th\u1ef1c thi b\u1edfi m\u00e1y t\u00ednh.<\/p>\n\n\n\n
Trong m\u1ed9t ng\u00f4n ng\u1eef l\u1eadp tr\u00ecnh, nh\u1eefng \u201cph\u1ea7n h\u01b0\u1edbng d\u1eabn\u201d \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 c\u00e2u l\u1ec7nh.<\/p>\n\n\n\n
Javascript l\u00e0 m\u1ed9t ng\u00f4n ng\u1eef l\u1eadp tr\u00ecnh.<\/p>\n\n\n\n
C\u00e1c c\u00e2u l\u1ec7nh trong Javascript \u0111\u01b0\u1ee3c ng\u0103n c\u00e1ch v\u1edbi nhau b\u1eb1ng d\u1ea5u ch\u1ea5m ph\u1ea9y.<\/p>\n\n\n\n
V\u00ed d\u1ee5:<\/p>\n\n\n\n
var x = 9;\nvar y = 3;\nvar z = x \u2013 y;<\/code><\/pre>\n\n\n\nTrong HTML, JavaScript c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c x\u1eed l\u00fd, th\u1ef1c thi b\u1eb1ng tr\u00ecnh duy\u1ec7t web (FireFox, Google Chorme, IE,..).<\/p>\n\n\n\n
PS: Vi\u1ec7c JS \u0111\u01b0\u1ee3c th\u1ef1c thi b\u1edfi tr\u00ecnh duy\u1ec7t n\u00ean n\u00f3 \u0111\u01b0\u1ee3c x\u1ebfp v\u00e0o nh\u00f3m ng\u00f4n ng\u1eef l\u1eadp tr\u00ecnh ph\u00eda m\u00e1y kh\u00e1ch. M\u1ed9t \u01b0u \u0111i\u1ec3m r\u1ea5t l\u1edbn \u0111\u1ed1i v\u1edbi ng\u00f4n ng\u1eef l\u1eadp tr\u00ecnh ph\u00eda m\u00e1y kh\u00e1ch l\u00e0 b\u1ea1n kh\u00f4ng t\u1ed1n t\u00e0i nguy\u00ean m\u00e1y ch\u1ee7 \u0111\u00e1ng k\u1ec3 \u0111\u1ec3 duy tr\u00ec d\u1ecbch v\u1ee5. Tuy nhi\u00ean n\u00f3 c\u0169ng c\u00f3 2 nh\u01b0\u1ee3c \u0111i\u1ec3m quan tr\u1ecdng:<\/p>\n\n\n\n
C\u00f3 th\u1ec3 c\u00f3 s\u1ef1 b\u1ea5t nh\u1ea5t trong vi\u1ec7c ph\u00e2n t\u00edch m\u00e3 c\u1ee7a tr\u00ecnh duy\u1ec7t, d\u1eabn \u0111\u1ebfn c\u00e1c k\u1ebft qu\u1ea3 kh\u00e1c nhau tr\u00ean c\u00e1c tr\u00ecnh duy\u1ec7t kh\u00e1c nhau;<\/li> M\u00e3 ngu\u1ed3n JS c\u1ee7a b\u1ea1n l\u00e0 c\u00f4ng khai, v\u00e0 ng\u01b0\u1eddi kh\u00e1c ho\u00e0n to\u00e0n sao ch\u00e9p \u0111\u01b0\u1ee3c. Hi\u1ec7n t\u00f4i kh\u00f4ng r\u00f5 c\u00e1c gi\u1ea3i ph\u00e1p m\u00e3 h\u00f3a nh\u1eb1m h\u1ea1n ch\u1ebf t\u00ecnh tr\u1ea1ng n\u00e0y t\u1ed1t \u0111\u1ebfn \u0111\u00e2u;<\/li><\/ul>\n\n\n\n \n\n\n\n<\/span>C\u00e2u l\u1ec7nh trong JavaScript<\/span><\/h2>\n\n\n\nC\u00e1c c\u00e2u l\u1ec7nh JavaScript \u0111\u01b0\u1ee3c t\u1ea1o th\u00e0nh t\u1eeb: Gi\u00e1 tr\u1ecb, To\u00e1n t\u1eed, Bi\u1ec3u th\u1ee9c, T\u1eeb kh\u00f3a v\u00e0 Ch\u00fa th\u00edch.<\/p>\n\n\n\n
\n\n\n\n<\/span>Gi\u00e1 tr\u1ecb trong JavaScript<\/span><\/h2>\n\n\n\nC\u00fa ph\u00e1p c\u1ee7a JavaScript \u0111\u1ecbnh ngh\u0129a 2 lo\u1ea1i gi\u00e1 tr\u1ecb: Gi\u00e1 tr\u1ecb c\u1ed1 \u0111\u1ecbnh v\u00e0 gi\u00e1 tr\u1ecb thay \u0111\u1ed5i. Gi\u00e1 tr\u1ecb c\u1ed1 \u0111\u1ecbnh \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 h\u1eb1ng, gi\u00e1 tr\u1ecb thay \u0111\u1ed5i \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 bi\u1ebfn.<\/p>\n\n\n\n
\n\n\n\n<\/span>H\u1eb1ng trong JavaScript<\/span><\/h2>\n\n\n\nNh\u1eefng lu\u1eadt quan tr\u1ecdng nh\u1ea5t khi vi\u1ebft c\u00e1c gi\u00e1 tr\u1ecb c\u1ed1 \u0111\u1ecbnh:<\/p>\n\n\n\n
S\u1ed1 \u0111\u01b0\u1ee3c vi\u1ebft v\u1edbi d\u1ea5u th\u1eadp ph\u00e2n ho\u1eb7c kh\u00f4ng c\u00f3 d\u1ea5u th\u1eadp ph\u00e2n: 10.501001<\/li> Chu\u1ed7i l\u00e0 v\u0103n b\u1ea3n, \u0111\u01b0\u1ee3c vi\u1ebft trong d\u1ea5u nh\u00e1y k\u00e9p ho\u1eb7c d\u1ea5u nh\u00e1y \u0111\u01a1n: “Ki\u1ebfn c\u00e0ng”; ‘HTML CSS JS’;<\/li> Bi\u1ec3u th\u1ee9c c\u00f3 th\u1ec3 l\u00e0 \u0111\u1ea1i di\u1ec7n cho gi\u00e1 tr\u1ecb c\u1ed1 \u0111\u1ecbnh: 5 + 6<\/em>5 * 10<\/li><\/ul>\n\n\n\n \n\n\n\n<\/span>Bi\u1ebfn trong JavaScript<\/span><\/h2>\n\n\n\nTrong ng\u00f4n ng\u1eef m\u00e1y t\u00ednh, bi\u1ebfn \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng \u0111\u1ec3 l\u01b0u tr\u1eef d\u1eef li\u1ec7u.<\/p>\n\n\n\n
Javascript s\u1eed d\u1ee5ng c\u00e1c bi\u1ebfn t\u1eeb kh\u00f3a \u0111\u1ec3 \u0111\u1ecbnh ngh\u0129a c\u00e1c gi\u00e1 tr\u1ecb thay \u0111\u1ed5i.<\/p>\n\n\n\n
K\u00fd hi\u1ec7u b\u1eb1ng ‘=’ \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng \u0111\u1ec3 g\u00e1n gi\u00e1 tr\u1ecb v\u00e0o bi\u1ebfn, ch\u1ee9 kh\u00f4ng ph\u1ea3i so s\u00e1nh b\u1eb1ng nhau.<\/p>\n\n\n\n
Trong v\u00ed d\u1ee5 b\u00ean d\u01b0\u1edbi, x l\u00e0 m\u1ed9t bi\u1ebfn. Sau \u0111\u00f3 ch\u00fang ta g\u00e1n cho n\u00f3 gi\u00e1 tr\u1ecb l\u00e0 blog Ki\u1ebfn c\u00e0ng.<\/p>\n\n\n\n
var x; \nx = \"blog Ki\u1ebfn c\u00e0ng\";<\/code><\/pre>\n\n\n\n \n\n\n\n<\/span>To\u00e1n t\u1eed trong JavaScript<\/span><\/h2>\n\n\n\nJavaScript s\u1eed d\u1ee5ng to\u00e1n t\u1eed g\u00e1n ‘=’ \u0111\u1ec3 g\u00e1n gi\u00e1 tr\u1ecb cho bi\u1ebfn:<\/p>\n\n\n\n
var x = 7;\nvar y = 9;<\/code><\/pre>\n\n\n\nJavaScript s\u1eed d\u1ee5ng c\u00e1c to\u00e1n t\u1eed s\u1ed1 h\u1ecdc ( + \u2013 * \/ ) \u0111\u1ec3 t\u00ednh to\u00e1n c\u00e1c gi\u00e1 tr\u1ecb, v\u00ed d\u1ee5: ((7 + 9) * 3) \/ 6<\/p>\n\n\n\n
\n\n\n\n<\/span>T\u1eeb kh\u00f3a trong JavaScript<\/span><\/h2>\n\n\n\nT\u1eeb kh\u00f3a trong JavaScript \u0111\u01b0\u1ee3c d\u00f9ng \u0111\u1ec3 x\u00e1c \u0111\u1ecbnh c\u00e1c h\u00e0nh \u0111\u1ed9ng \u0111\u01b0\u1ee3c th\u1ef1c hi\u1ec7n.<\/p>\n\n\n\n
V\u00ed d\u1ee5 t\u1eeb kh\u00f3a var<\/code> n\u00f3i cho tr\u00ecnh duy\u1ec7t bi\u1ebft c\u1ea7n t\u1ea1o m\u1ed9t bi\u1ebfn m\u1edbi:<\/p>\n\n\n\nvar x = 5 ;\nvar y = x + 3;<\/code><\/pre>\n\n\n\n \n\n\n\n<\/span>Ch\u00fa th\u00edch trong JavaScript<\/span><\/h2>\n\n\n\nKh\u00f4ng ph\u1ea3i t\u1ea5t c\u1ea3 c\u00e1c c\u00e2u l\u1ec7nh JavaScript \u0111\u1ec1u \u0111\u01b0\u1ee3c th\u1ef1c thi.<\/p>\n\n\n\n
Code \u0111\u1ee9ng sau 2 g\u1ea1ch x\u1ed5 \/\/<\/code> (cho lo\u1ea1i m\u1ed9t d\u00f2ng) ho\u1eb7c n\u1eb1m gi\u1eefa \/*<\/code> v\u00e0 *\/<\/code> (cho lo\u1ea1i nhi\u1ec1u d\u00f2ng) \u0111\u01b0\u1ee3c x\u00e1c \u0111\u1ecbnh l\u00e0 comment.<\/p>\n\n\n\nCh\u00fa th\u00edch s\u1ebd b\u1ecb b\u1ecf qua v\u00e0 kh\u00f4ng \u0111\u01b0\u1ee3c th\u1ef1c thi:<\/p>\n\n\n\n
var x = 7; \/\/ C\u00e2u l\u1ec7nh n\u00e0y s\u1ebd \u0111\u01b0\u1ee3c th\u1ef1c thi\n\/\/ var x = 6; C\u00e2u l\u1ec7nh n\u00e0y kh\u00f4ng \u0111\u01b0\u1ee3c th\u1ef1c thi<\/code><\/pre>\n\n\n\n \n\n\n\n<\/span>JavaScript l\u00e0 ng\u00f4n ng\u1eef nh\u1ea1y c\u1ea3m v\u1edbi c\u00e1ch VI\u1ebeT HOA hay vi\u1ebft th\u01b0\u1eddng<\/span><\/h2>\n\n\n\nDo v\u1eady hai bi\u1ebfn lastName<\/code> v\u00e0 lastname<\/code> l\u00e0 hai bi\u1ebfn ho\u00e0n to\u00e0n kh\u00e1c nhau.<\/p>\n\n\n\nlastName = \"Nguy\u1ec5n\";\nlastname = \"Tr\u1ea7n\";<\/code><\/pre>\n\n\n\nJavascript s\u1ebd kh\u00f4ng chuy\u1ec3n \u0111\u1ed5i c\u00e1ch vi\u1ebft VAR ho\u1eb7c Var th\u00e0nh t\u1eeb kh\u00f3a var<\/code>. T\u1ee9c l\u00e0 2 c\u00e2u l\u1ec7nh c\u00f3 ch\u1eef hoa \u1edf tr\u00ean (VAR v\u00e0 Var) s\u1ebd kh\u00f4ng \u0111\u01b0\u1ee3c th\u1ef1c thi.<\/p>\n\n\n\nTh\u00f4ng th\u01b0\u1eddng, trong JavaScript, c\u00e1ch vi\u1ebft th\u01b0\u1eddng Hoa li\u1ec1n nhau d\u00e0nh cho t\u00ean bi\u1ebfn r\u1ea5t ph\u1ed5 bi\u1ebfn. B\u1ea1n s\u1ebd th\u1ea5y c\u00e1ch vi\u1ebft d\u01b0\u1edbi d\u1ea1ng lastName<\/code> \u0111\u01b0\u1ee3c \u01b0a d\u00f9ng h\u01a1n lastname<\/code> (c\u00e1ch vi\u1ebft lastName gi\u00fap ch\u00fang ta d\u1ec5 \u0111\u1ecdc h\u01a1n h\u1eb3n).<\/p>\n","protected":false},"excerpt":{"rendered":"C\u00fa ph\u00e1p trong JavaScript l\u00e0 c\u00e1c quy t\u1eafc, c\u00e1ch th\u1ee9c c\u00e1c ch\u01b0\u01a1ng tr\u00ecnh JavaScript \u0111\u01b0\u1ee3c x\u00e2y d\u1ef1ng. Ng\u00f4n ng\u1eef Javascript l\u00e0 g\u00ec? M\u1ed9t ng\u00f4n ng\u1eef m\u00e1y t\u00ednh l\u00e0 danh s\u00e1ch c\u00e1c h\u01b0\u1edbng d\u1eabn \u0111\u01b0\u1ee3c th\u1ef1c thi b\u1edfi m\u00e1y t\u00ednh. Trong m\u1ed9t ng\u00f4n ng\u1eef l\u1eadp tr\u00ecnh, nh\u1eefng \u201cph\u1ea7n h\u01b0\u1edbng d\u1eabn\u201d \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 c\u00e2u l\u1ec7nh. Javascript …<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[236],"tags":[],"yoast_head":"\n
C\u00fa ph\u00e1p trong JavaScript • Ki\u1ebfn c\u00e0ng<\/title>\n \n \n \n \n \n \n \n \n \n \n \n \n \n\t \n\t \n\t \n","yoast_head_json":{"title":"C\u00fa ph\u00e1p trong JavaScript • Ki\u1ebfn c\u00e0ng","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/kiencang.net\/cu-phap-trong-javascript\/","og_locale":"vi_VN","og_type":"article","og_title":"C\u00fa ph\u00e1p trong JavaScript • Ki\u1ebfn c\u00e0ng","og_description":"C\u00fa ph\u00e1p trong JavaScript l\u00e0 c\u00e1c quy t\u1eafc, c\u00e1ch th\u1ee9c c\u00e1c ch\u01b0\u01a1ng tr\u00ecnh JavaScript \u0111\u01b0\u1ee3c x\u00e2y d\u1ef1ng. Ng\u00f4n ng\u1eef Javascript l\u00e0 g\u00ec? M\u1ed9t ng\u00f4n ng\u1eef m\u00e1y t\u00ednh l\u00e0 danh s\u00e1ch c\u00e1c h\u01b0\u1edbng d\u1eabn \u0111\u01b0\u1ee3c th\u1ef1c thi b\u1edfi m\u00e1y t\u00ednh. Trong m\u1ed9t ng\u00f4n ng\u1eef l\u1eadp tr\u00ecnh, nh\u1eefng \u201cph\u1ea7n h\u01b0\u1edbng d\u1eabn\u201d \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 c\u00e2u l\u1ec7nh. Javascript …","og_url":"https:\/\/kiencang.net\/cu-phap-trong-javascript\/","og_site_name":"Ki\u1ebfn c\u00e0ng","article_author":"https:\/\/www.facebook.com\/anhducnguyen87\/","article_published_time":"2015-01-23T08:40:00+00:00","author":"Nguy\u1ec5n \u0110\u1ee9c Anh","twitter_card":"summary_large_image","twitter_misc":{"\u0110\u01b0\u1ee3c vi\u1ebft b\u1edfi":"Nguy\u1ec5n \u0110\u1ee9c Anh","\u01af\u1edbc t\u00ednh th\u1eddi gian \u0111\u1ecdc":"4 ph\u00fat"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"WebPage","@id":"https:\/\/kiencang.net\/cu-phap-trong-javascript\/","url":"https:\/\/kiencang.net\/cu-phap-trong-javascript\/","name":"C\u00fa ph\u00e1p trong JavaScript • Ki\u1ebfn c\u00e0ng","isPartOf":{"@id":"https:\/\/kiencang.net\/#website"},"datePublished":"2015-01-23T08:40:00+00:00","dateModified":"2015-01-23T08:40:00+00:00","author":{"@id":"https:\/\/kiencang.net\/#\/schema\/person\/5e7e1a04d8d1218ad8c421ba43d25c16"},"breadcrumb":{"@id":"https:\/\/kiencang.net\/cu-phap-trong-javascript\/#breadcrumb"},"inLanguage":"vi","potentialAction":[{"@type":"ReadAction","target":["https:\/\/kiencang.net\/cu-phap-trong-javascript\/"]}]},{"@type":"BreadcrumbList","@id":"https:\/\/kiencang.net\/cu-phap-trong-javascript\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/kiencang.net\/"},{"@type":"ListItem","position":2,"name":"C\u00fa ph\u00e1p trong JavaScript"}]},{"@type":"WebSite","@id":"https:\/\/kiencang.net\/#website","url":"https:\/\/kiencang.net\/","name":"Ki\u1ebfn c\u00e0ng","description":"\u00d4m l\u00fd thuy\u1ebft, h\u00f4n th\u1ef1c h\u00e0nh","potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/kiencang.net\/?s={search_term_string}"},"query-input":"required name=search_term_string"}],"inLanguage":"vi"},{"@type":"Person","@id":"https:\/\/kiencang.net\/#\/schema\/person\/5e7e1a04d8d1218ad8c421ba43d25c16","name":"Nguy\u1ec5n \u0110\u1ee9c Anh","image":{"@type":"ImageObject","inLanguage":"vi","@id":"https:\/\/kiencang.net\/#\/schema\/person\/image\/","url":"https:\/\/secure.gravatar.com\/avatar\/6d71f9b89393952a8382e30dad26c1ec?s=96&d=monsterid&r=g","contentUrl":"https:\/\/secure.gravatar.com\/avatar\/6d71f9b89393952a8382e30dad26c1ec?s=96&d=monsterid&r=g","caption":"Nguy\u1ec5n \u0110\u1ee9c Anh"},"description":"Sinh n\u0103m 1987, t\u1ed1t nghi\u1ec7p Cao \u0111\u1eb3ng th\u1ef1c h\u00e0nh FPT qu\u00e3ng 2014, chuy\u00ean ng\u00e0nh Thi\u1ebft k\u1ebf website. T\u00f4i th\u00edch Content, SEO, Ads, T\u0103ng t\u1ed1c website v\u00e0 Th\u01b0\u01a1ng m\u1ea1i \u0111i\u1ec7n t\u1eed. B\u00ean c\u1ea1nh b\u00e0i t\u1ef1 vi\u1ebft, t\u00f4i c\u0169ng d\u1ecbch nhi\u1ec1u n\u1ed9i dung th\u00fa v\u1ecb c\u1ee7a c\u00e1c t\u00e1c gi\u1ea3 kh\u00e1c nhau. FB c\u00e1 nh\u00e2n: facebook.com\/anhducnguyen87. Email li\u00ean h\u1ec7: guiemailchotoi@gmail.com","sameAs":["https:\/\/www.facebook.com\/anhducnguyen87\/"],"url":"https:\/\/kiencang.net\/author\/admin\/"}]}},"_links":{"self":[{"href":"https:\/\/kiencang.net\/wp-json\/wp\/v2\/posts\/25"}],"collection":[{"href":"https:\/\/kiencang.net\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/kiencang.net\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/kiencang.net\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/kiencang.net\/wp-json\/wp\/v2\/comments?post=25"}],"version-history":[{"count":0,"href":"https:\/\/kiencang.net\/wp-json\/wp\/v2\/posts\/25\/revisions"}],"wp:attachment":[{"href":"https:\/\/kiencang.net\/wp-json\/wp\/v2\/media?parent=25"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kiencang.net\/wp-json\/wp\/v2\/categories?post=25"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kiencang.net\/wp-json\/wp\/v2\/tags?post=25"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}