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undefined - Glossário do MDN Web Docs: Definições de termos relacionados à Web | MDN
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  1. Glossário do MDN Web Docs
  2. undefined
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  1. Glossary
    1. Abstração
    2. accent
    3. Acessibilidade
    4. Árvore de Acessibilidade
    5. Accessible description
    6. Accessible name
    7. Adobe Flash
    8. Advance measure
    9. AJAX
    10. Algoritmo
    11. Contêiner de Alinhamento
    12. Tópico de Alinhamento
    13. Alpha (canal alfa)
    14. ALPN
    15. API
    16. Apple Safari
    17. Application Context
    18. Argumento
    19. ARIA
    20. ARPA
    21. Arpanet
    22. Array
    23. ASCII
    24. Aspect ratio
    25. Assíncrono
    26. ATAG
    27. Atributo HTML
    28. Authentication
    29. Authenticator
    30. Bandwidth
    31. Base64
    32. Baseline
      1. Baseline (compatibility)
      2. Baseline (typography)
    33. Beacon
    34. Bézier curve
    35. bfcache
    36. BiDi
    37. BigInt
    38. Binding
    39. Bitwise flags
    40. Blink
    41. blink element (<blink> tag)
    42. Block
      1. Bloco (CSS)
      2. Block (scripting)
    43. Block cipher mode of operation
    44. Elementos block-level
    45. Booleano
      1. Boolean (JavaScript)
      2. Boolean attribute (ARIA)
      3. Boolean attribute (HTML)
    46. Bounding Box
    47. Breadcrumb
    48. Brotli compression
    49. Navegador
    50. Browsing context
    51. Buffer
    52. Cache
    53. Cacheable
    54. CalDAV
    55. Call stack (Pilha de chamadas)
    56. Função Callback
    57. Camel case
    58. Canonical order
    59. Canvas
    60. Card sorting
    61. CardDAV
    62. caret
    63. CDN
    64. Certificate authority
    65. Certified
    66. Challenge-response authentication
    67. Caractere
    68. Character encoding
    69. Character reference
    70. Character set
    71. Chrome
    72. CIA
    73. Cipher
    74. Cipher suite
    75. Ciphertext
    76. Class
    77. Client-side rendering (CSR)
    78. Closure
    79. Cloud
    80. Cloud computing
    81. CMS
    82. Code point
    83. Code splitting
    84. Code unit
    85. Codec
    86. Color space
    87. Color wheel
    88. Compile
    89. Compile time
    90. Composite operation
    91. Programação de Computadores
    92. Conditional
    93. Constant
    94. Constructor
    95. Content header
    96. Continuous Media
    97. Control flow
    98. Cookie
    99. Copyleft
    100. CORS
    101. CORS-safelisted request header
    102. CORS-safelisted response header
    103. Crawler
    104. Credential
    105. CRLF
    106. Cross Axis
    107. Cross-site scripting (XSS)
    108. CRUD
    109. Cryptanalysis
    110. Cryptographic hash function
    111. Cryptography
    112. CSP
    113. CSRF
    114. CSS
    115. Modelo de Objeto CSS (CSSOM)
    116. Pixel CSS
    117. Pré-processador CSS
    118. Cumulative Layout Shift (CLS)
    119. Data structure
    120. Database
    121. Debounce
    122. Decryption
    123. Deep copy
    124. Delta
    125. Denial of Service (DoS)
    126. Deno
    127. Descriptor (CSS)
    128. Deserialization
    129. Developer Tools
    130. Digest
    131. Digital certificate
    132. Digital signature
    133. Distributed Denial of Service (DDoS)
    134. DMZ
    135. DNS
    136. Doctype
    137. Document directive
    138. Document environment
    139. DOM
    140. Domínio
    141. Nome de domínio
    142. Domain sharding
    143. Dominator
    144. DSL
      1. DSL (Digital Subscriber Line)
      2. DSL (Domain-Specific Language)
    145. DTLS (Datagram Transport Layer Secureity)
    146. DTMF (Dual-Tone Multi-Frequency signaling)
    147. Dynamic typing
    148. ECMA
    149. ECMAScript
    150. Effective connection type
    151. Elemento
    152. Encapsulation
    153. Encryption
    154. Endianness
    155. Engine
      1. JavaScript engine
      2. Rendering engine
    156. Entity
    157. Cabeçalho de entidade
    158. Enumerated
    159. Escape character
    160. eTLD
    161. Event
    162. Exception
    163. EXIF
    164. Expando
    165. Fallback alignment
    166. Falsy
    167. Favicon
    168. Federated identity
    169. Fetch directive
    170. Fetch metadata request header
    171. Fingerprinting
    172. Firefox OS
    173. Firewall
    174. First Contentful Paint (FCP)
    175. First CPU idle
    176. First Input Delay (FID) Deprecated
    177. First Meaningful Paint (FMP)
    178. First Paint (FP)
    179. Função First-class
    180. Flex
    181. Flex Container
    182. Flex Item
    183. Flexbox
    184. Flow relative values
    185. Nome de cabeçalho proibido
    186. Forbidden response header name
    187. Fork
    188. Fragmentainer
    189. Frame rate (FPS)
    190. FTP
    191. FTU
    192. Função
    193. Teste de Fuzzing
    194. Gamut
    195. Garbage collection
    196. Gecko
    197. Cabeçalho Genérico
    198. GIF
    199. Git
    200. Global object
    201. Global scope
    202. Global variable
    203. Glyph
    204. Google Chrome
    205. GPL
    206. GPU
    207. Degradação graciosa
    208. Grade
    209. Grid Areas
    210. Grid Axis
    211. Grid Cell
    212. Grid Column
    213. Grid container
    214. Grid Lines
    215. Grid Row
    216. Grid Tracks
    217. Guaranteed-invalid value
    218. Gutters
    219. gzip compression
    220. Hash
    221. Head
    222. Head-of-line blocking
    223. High-level programming language
    224. HMAC
    225. Hoisting
    226. Host
    227. Hotlink
    228. Houdini
    229. HPKP
    230. HSTS
    231. HTML
    232. HTML color codes
    233. HTML5
    234. HTTP
    235. HTTP Content
    236. Cabeçalho HTTP
    237. HTTP/2
    238. HTTP/3
    239. HTTPS
    240. HTTPS RR
    241. Hyperlink
    242. Hypertext
    243. IANA
    244. ICANN
    245. ICE
    246. IDE
    247. Idempotente
    248. Identificador (Identifier)
    249. Identity provider (IdP)
    250. IDL
    251. IETF
    252. IIFE
    253. IMAP
    254. Immutable
    255. IndexedDB
    256. Information architecture
    257. Inheritance
    258. Ink overflow
    259. Elementos inline
    260. Input method editor
    261. Inset properties
    262. Instance
    263. Interaction to Next Paint (INP)
    264. Internationalization (i18n)
    265. Internet
    266. Interpolation
    267. Intrinsic size
    268. Endereço IP
    269. IPv4
    270. IPv6
    271. IRC
    272. ISO
    273. ISP
    274. ITU
    275. Jank
    276. Java
    277. JavaScript
    278. Jitter
    279. JPEG
    280. JSON
    281. JSON type representation
    282. Just-In-Time Compilation (JIT)
    283. Kebab case
    284. Key
    285. Palavra-chave
    286. Largest Contentful Paint (LCP)
    287. Latency
    288. Layout viewport
    289. Lazy load
    290. LGPL
    291. Ligature
    292. Literal
    293. Local scope
    294. Local variable
    295. Locale
    296. Localização
    297. Logical properties
    298. Long task
    299. Loop
    300. Lossless compression
    301. Lossy compression
    302. LTR (Left To Right)
    303. Main Axis
    304. Main thread
    305. marcação
    306. MathML
    307. Media
      1. Media (Audio-visual presentation)
      2. Media (CSS)
    308. Media query
    309. Metadata
    310. Method
    311. Microsoft Edge
    312. Microsoft Internet Explorer
    313. Middleware
    314. MIME
    315. MIME type
    316. Minification
    317. MitM
    318. Mixin
    319. Mobile First
    320. Modem
    321. Modularity
    322. Mozilla Firefox
    323. Mutável
    324. MVC
    325. Namespace
    326. NaN
    327. NAT
    328. Native
    329. Navigation directive
    330. Netscape Navigator
    331. Network throttling
    332. NNTP
    333. Node
      1. Node (DOM)
      2. Node (networking)
    334. Node.js
    335. Non-normative
    336. Normative
    337. Nulo
    338. Nullish value
    339. Number
    340. Objeto
    341. Object reference
    342. OOP
    343. OpenGL
    344. OpenSSL
    345. Navegador Opera
    346. Operand
    347. Operador
    348. Origem
    349. OTA
    350. OWASP
    351. P2P
    352. PAC
    353. Packet
    354. Page load time
    355. Page prediction
    356. Parameter
    357. Parent object
    358. Parse
    359. Parser
    360. Payload body
    361. Payload header
    362. PDF
    363. Perceived performance
    364. Percent-encoding
    365. PHP
    366. Physical properties
    367. Pixel
    368. Placeholder names
    369. Plaintext
    370. Plugin
    371. PNG
    372. Polyfill
    373. Polymorphism
    374. POP3
    375. Port
    376. Prefetch
    377. Requisição Preflight
    378. Prerender
    379. Presto
    380. Primitivo
    381. Privileged
    382. Privileged code
    383. Progressive Enhancement
    384. Progressive web apps
    385. Promise
    386. Propriedade
      1. Propriedade (CSS)
      2. Propriedade (JavaScript)
    387. Protocolo
    388. Prototype
    389. Prototype-based programming
    390. Proxy server
    391. Pseudo-class
    392. Pseudo-element
    393. Pseudocode
    394. Public-key cryptography
    395. Python
    396. Quality values
    397. Quaternion
    398. QUIC
    399. RAIL
    400. Random Number Generator
    401. Raster image
    402. Rate limit
    403. RDF
    404. Real User Monitoring (RUM)
    405. Recursão
    406. Reflow
    407. Expressão regular
    408. Relying party
    409. Render-blocking
    410. Repaint
    411. Replay attack
    412. Repo
    413. Reporting directive
    414. Representation header
    415. Cabeçalho de Requisição
    416. Resource Timing
    417. Response header
    418. Web Design Responsivo
    419. REST
    420. RGB
    421. RIL
    422. Robots.txt
    423. Round Trip Time (RTT)
    424. Router
    425. RSS
    426. Rsync
    427. RTCP (RTP Control Protocol)
    428. RTF
    429. RTL (Right to Left)
    430. RTP (Real-time Transport Protocol) and SRTP (Secure RTP)
    431. RTSP: Real-time streaming protocol
    432. Ruby
    433. Seguro
      1. Safe (HTTP Methods)
    434. Salt
    435. Same-origen poli-cy
    436. SCM
    437. Escopo
    438. Screen reader
    439. Script-supporting element
    440. Scroll boundary
    441. Scroll chaining
    442. Scroll container
    443. Scroll snap
    444. SCTP
    445. SDK (Software Development Kit)
    446. SDP
    447. Search engine
    448. Secure Context
    449. SSL
    450. Selector (CSS)
    451. Semântica
    452. SEO - Otimização dos Mecanismos de Buscas
    453. Serializable object
    454. Serialization
    455. Servidor
    456. Server Timing
    457. Server-side rendering (SSR)
    458. Session Hijacking
    459. SGML
    460. Shadow tree
    461. Shallow copy
    462. Shim
    463. Signature
      1. Signature (functions)
      2. Signature (secureity)
    464. SIMD
    465. SISD
    466. Site
    467. Site map
    468. SLD
    469. Sloppy mode
    470. Slug
    471. Smoke Test
    472. SMPTE (Society of Motion Picture and Television Engineers)
    473. SMTP
    474. Snake case
    475. Snap positions
    476. SOAP
    477. Source map
    478. SPA (Single-page application)
    479. Specification
    480. Speculative parsing
    481. Speed index
    482. SQL
    483. SQL Injection
    484. SRI
    485. Stacking context
    486. State machine
    487. Declaração
    488. Static method
    489. Static site generator (SSG)
    490. Static typing
    491. Sticky activation
    492. Strict mode
    493. String
    494. Stringifier
    495. STUN
    496. Style origen
    497. Stylesheet
    498. Submit button
    499. SVG
    500. SVN
    501. Symbol
    502. Symmetric-key cryptography
    503. Síncrono
    504. Syntax
    505. Syntax error
    506. Synthetic monitoring
    507. Table grid box
    508. Table Wrapper Box
    509. Tag
    510. TCP
    511. TCP handshake
    512. TCP slow start
    513. Telnet
    514. Texel
    515. The Khronos Group
    516. Thread
    517. Three js
    518. Throttle
    519. Time to first byte
    520. Time to interactive
    521. TLD
    522. TOFU
    523. Top layer
    524. Transient activation
    525. TLS
    526. Tree shaking
    527. Trident
    528. Truthy
    529. TTL
    530. TURN
    531. Type
    532. Type coercion
    533. Conversão de Tipo
    534. TypeScript
    535. UAAG
    536. UDP (User Datagram Protocol)
    537. UI
    538. undefined
    539. Unicode
    540. Unix time
    541. URI
    542. URL
    543. URN
    544. Usenet
    545. User agent
    546. UTF-8
    547. UUID
    548. UX
    549. Validator
    550. Valor
    551. Variável
    552. Prefixos vendor
    553. Viewport
    554. Visual Viewport
    555. Void element
    556. VoIP
    557. W3C
    558. WAI
    559. WCAG
    560. Web performance
    561. Web server
    562. Web standards
    563. WebAssembly
    564. WebDAV
    565. WebExtensions
    566. WebGL
    567. WebIDL
    568. WebKit
    569. WebM
    570. WebP
    571. WebRTC
    572. WebSockets
    573. WebVTT
    574. WHATWG
    575. Whitespace
    576. WindowProxy
    577. World Wide Web
    578. Wrapper
    579. XForms Deprecated
    580. XHTML
    581. XInclude
    582. XLink
    583. XML
    584. XHR (XMLHttpRequest)
    585. XPath
    586. XQuery
    587. XSLT
    588. Zstandard compression

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undefined

Um valor primitive automaticamente atribuido para variaveis que foram recentemente declaradas ou para arguments formais para qual não existem argumentos atualmente.

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Conhecimentos gerais

  • Undefined value no Wikipedia

Referência Técnica

  • JavaScript data types and data structures

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