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  1. Glossário do MDN Web Docs
  2. undefined
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  1. Glossário do MDN Web Docs
    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
    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
    43. Block cipher mode of operation
    44. Elementos block-level
    45. Booleano
    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. Clickjacking
    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
    126. Deno
    127. Descriptor (CSS)
    128. Deserialization
    129. Developer Tools
    130. Digest
    131. Digital certificate
    132. Digital signature
    133. Distributed Denial of Service
    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. DoS attack
    145. DSL
    146. DTLS (Datagram Transport Layer Security)
    147. DTMF (Dual-Tone Multi-Frequency signaling)
    148. Dynamic typing
    149. ECMA
    150. ECMAScript
    151. Effective connection type
    152. Elemento
    153. Encapsulation
    154. Encryption
    155. Endianness
    156. Engine
    157. Entity
    158. Cabeçalho de entidade
    159. Enumerated
    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
    175. First CPU idle
    176. First input delay
    177. First Meaningful Paint
    178. First paint
    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. Gutters
    218. gzip compression
    219. Hash
    220. Head
    221. High-level programming language
    222. HMAC
    223. Hoisting
    224. Host
    225. Hotlink
    226. Houdini
    227. HPKP
    228. HSTS
    229. HTML
    230. HTML color codes
    231. HTML5
    232. HTTP
    233. HTTP Content
    234. Cabeçalho HTTP
    235. HTTP/2
    236. HTTP/3
    237. HTTPS
    238. HTTPS RR
    239. Hyperlink
    240. Hypertext
    241. IANA
    242. ICANN
    243. ICE
    244. IDE
    245. Idempotente
    246. Identificador (Identifier)
    247. Identity provider (IdP)
    248. IDL
    249. IETF
    250. IIFE
    251. IMAP
    252. Immutable
    253. IndexedDB
    254. Information architecture
    255. Inheritance
    256. Ink overflow
    257. Elementos inline
    258. Input method editor
    259. Inset properties
    260. Instance
    261. Internationalization (i18n)
    262. Internet
    263. Interpolation
    264. Intrinsic size
    265. Endereço IP
    266. IPv4
    267. IPv6
    268. IRC
    269. ISO
    270. ISP
    271. ITU
    272. Jank
    273. Java
    274. JavaScript
    275. Jitter
    276. JPEG
    277. JSON
    278. JSON type representation
    279. Kebab case
    280. Key
    281. Palavra-chave
    282. Largest contentful paint
    283. Latency
    284. Layout viewport
    285. Lazy load
    286. LGPL
    287. Ligature
    288. Literal
    289. Local scope
    290. Local variable
    291. Locale
    292. Localização
    293. Logical properties
    294. Long task
    295. Loop
    296. Lossless compression
    297. Lossy compression
    298. LTR (Left To Right)
    299. Main Axis
    300. Main thread
    301. marcação
    302. MathML
    303. Media
    304. Media query
    305. Metadata
    306. Method
    307. Microsoft Edge
    308. Microsoft Internet Explorer
    309. Middleware
    310. MIME
    311. MIME type
    312. Minification
    313. MitM
    314. Mixin
    315. Mobile First
    316. Modem
    317. Modularity
    318. Mozilla Firefox
    319. Mutável
    320. MVC
    321. Namespace
    322. NaN
    323. NAT
    324. Native
    325. Navigation directive
    326. Netscape Navigator
    327. Network throttling
    328. NNTP
    329. Node
    330. Node.js
    331. Non-normative
    332. Normative
    333. Nulo
    334. Nullish value
    335. Number
    336. Objeto
    337. Object reference
    338. OOP
    339. OpenGL
    340. OpenSSL
    341. Navegador Opera
    342. Operand
    343. Operador
    344. Origem
    345. OTA
    346. OWASP
    347. P2P
    348. PAC
    349. Packet
    350. Page load time
    351. Page prediction
    352. Parameter
    353. Parent object
    354. Parse
    355. Parser
    356. Payload body
    357. Payload header
    358. PDF
    359. Perceived performance
    360. Percent-encoding
    361. PHP
    362. Physical properties
    363. Pixel
    364. Placeholder names
    365. Plaintext
    366. Plugin
    367. PNG
    368. Polyfill
    369. Polymorphism
    370. POP3
    371. Port
    372. Prefetch
    373. Requisição Preflight
    374. Prerender
    375. Presto
    376. Primitivo
    377. Privileged
    378. Privileged code
    379. Progressive Enhancement
    380. Progressive web apps
    381. Promise
    382. Propriedade
    383. Protocolo
    384. Prototype
    385. Prototype-based programming
    386. Proxy server
    387. Pseudo-class
    388. Pseudo-element
    389. Pseudocode
    390. Public-key cryptography
    391. Python
    392. Quality values
    393. Quaternion
    394. QUIC
    395. RAIL
    396. Random Number Generator
    397. Raster image
    398. Rate limit
    399. RDF
    400. Real User Monitoring (RUM)
    401. Recursão
    402. Reflow
    403. Expressão regular
    404. Relying party
    405. Render-blocking
    406. Repaint
    407. Replay attack
    408. Repo
    409. Reporting directive
    410. Representation header
    411. Cabeçalho de Requisição
    412. Resource Timing
    413. Response header
    414. Web Design Responsivo
    415. REST
    416. RGB
    417. RIL
    418. Robots.txt
    419. Round Trip Time (RTT)
    420. Router
    421. RSS
    422. Rsync
    423. RTCP (RTP Control Protocol)
    424. RTF
    425. RTL (Right to Left)
    426. RTP (Real-time Transport Protocol) and SRTP (Secure RTP)
    427. RTSP: Real-time streaming protocol
    428. Ruby
    429. Seguro
    430. Salt
    431. Same-origin policy
    432. SCM
    433. Escopo
    434. Screen reader
    435. Script-supporting element
    436. Scroll boundary
    437. Scroll chaining
    438. Scroll container
    439. Scroll snap
    440. SCTP
    441. SDK (Software Development Kit)
    442. SDP
    443. Search engine
    444. Secure Context
    445. SSL
    446. Selector (CSS)
    447. Self-Executing Anonymous Function
    448. Semântica
    449. SEO - Otimização dos Mecanismos de Buscas
    450. Serializable object
    451. Serialization
    452. Servidor
    453. Server Timing
    454. Session Hijacking
    455. SGML
    456. Shadow tree
    457. Shallow copy
    458. Shim
    459. Signature
    460. SIMD
    461. SISD
    462. Site
    463. Site map
    464. SLD
    465. Sloppy mode
    466. Slug
    467. Smoke Test
    468. SMPTE (Society of Motion Picture and Television Engineers)
    469. SMTP
    470. Snake case
    471. Snap positions
    472. SOAP
    473. SPA (Single-page application)
    474. Specification
    475. Speculative parsing
    476. Speed index
    477. SQL
    478. SQL Injection
    479. SRI
    480. Stacking context
    481. State machine
    482. Declaração
    483. Static method
    484. Static site generator (SSG)
    485. Static typing
    486. Sticky activation
    487. Strict mode
    488. String
    489. Stringifier
    490. STUN
    491. Style origin
    492. Stylesheet
    493. Submit button
    494. SVG
    495. SVN
    496. Symbol
    497. Symmetric-key cryptography
    498. Síncrono
    499. Syntax
    500. Syntax error
    501. Synthetic monitoring
    502. Table grid box
    503. Table Wrapper Box
    504. Tag
    505. TCP
    506. TCP handshake
    507. TCP slow start
    508. Telnet
    509. Texel
    510. The Khronos Group
    511. Thread
    512. Three js
    513. Throttle
    514. Time to first byte
    515. Time to interactive
    516. TLD
    517. TOFU
    518. Top layer
    519. Transient activation
    520. TLS
    521. Tree shaking
    522. Trident
    523. Truthy
    524. TTL
    525. TURN
    526. Type
    527. Type coercion
    528. Conversão de Tipo
    529. TypeScript
    530. UAAG
    531. UDP (User Datagram Protocol)
    532. UI
    533. undefined
    534. Unicode
    535. Unix time
    536. URI
    537. URL
    538. URN
    539. Usenet
    540. User agent
    541. UTF-8
    542. UUID
    543. UX
    544. Validator
    545. Valor
    546. Variável
    547. Prefixos vendor
    548. Viewport
    549. Visual Viewport
    550. Void element
    551. VoIP
    552. W3C
    553. WAI
    554. WCAG
    555. Web performance
    556. Web server
    557. Web standards
    558. WebAssembly
    559. WebDAV
    560. WebExtensions
    561. WebGL
    562. WebIDL
    563. WebKit
    564. WebM
    565. WebP
    566. WebRTC
    567. WebSockets
    568. WebVTT
    569. WHATWG
    570. Whitespace
    571. WindowProxy
    572. World Wide Web
    573. Wrapper
    574. XForms Deprecated
    575. XHTML
    576. XInclude
    577. XLink
    578. XML
    579. XHR (XMLHttpRequest)
    580. XPath
    581. XQuery
    582. XSLT
    583. 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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