preface
The main content includes HTML, CSS, front-end foundation, front-end core, front-end advancement, mobile terminal development, computer foundation, algorithms and data structures, design patterns, projects and so on. (The data in this paper are suitable for 0-2 years)
It includes questions asked by first-tier Internet companies such as Tencent, Bytedance, Xiaomi, Ali, Didi, Meituan, 58, Pindoduo, 360, Sina, Sohu and so on, covering the primary and intermediate front-end technology points.
Listed in the article is mainly the outline part, the details can be obtained at the end of the article!
The first chapter HTML
1. What are the three layers of a browser page?
2. Advantages and disadvantages of HTML5?
3. The Doctype? How to distinguish strict mode from promiscuous mode? What do they mean?
4. What are the new features and elements removed from HTML5?
5. In which browsers have you tested your web pages, and what are their kernels?
6. There is an important thing at the beginning of every HTML file, Doctype.
7. Tell me what you know about HTML5? (What and why)
8. Understanding of WEB standards and W3C?
9. What are HTML5 inline elements, block-level elements, and empty elements?
10. What is WebGL and what are its advantages?
11. Please describe the difference between cookies, sessionStorage and localStorage.
12. Tell me your understanding of HTML semantics.
13. What is the difference between link and @import?
14. Tell me what you understand about SVG.
15. What are HTML global attributes?
16. Describe the value and function of the hyperlink target attribute.
17. Data – What does the attribute do?
18. What is your understanding of browser kernel?
19. What are common browser kernels?
20. What are the disadvantages of iframe?
21. What is the function of Label and how is it used?
22. How to implement communication between multiple tabs in the browser?
23. How to create a circular clickable area on a page?
24. What is the difference between title and H3, B and strong, I and EM?
25. Do not use the border to draw a 1px high line, will be consistent across browsers in standard mode and weird mode?
26. What do HTML5 tags do? (purpose)
27. Describe the difference between SRC and href.
28. What is your understanding of Canvas?
29.WebSocket and Message push?
30. What is the difference between MG title and Alt?
31. What are the basic components of forms and what are the main uses of forms?
32. What is the difference between Get and Post in form submission?
33. What are the new form elements in HTML5?
34. What HTML4 tags did HTML5 scrap?
35. What new apis does the HTML5 standard provide?
36. What is the difference between HTML5 storage types?
37. What is the difference between HTML5 application caching and browser caching?
38. What is the use of the HTML5 Canvas element?
39. Besides audio and video, what other media tags do HTML5 have?
40. How to embed video in HTML5?
41. How to embed audio in HTML5?
42. What are the new HTML5 document types and character sets?
The second chapter CSS
1. Explain the CSS box model?
2. Describe the types of CSS selectors and give some examples of their use.
3. What is special about CSS? (Priority, calculate special value)
4. Want to dynamically change the way content in the layer can be used?
5. Common browser compatibility problems and solutions?
6. List the values of display and say what they do.
7. How do I center a div, a floating element?
8. What is the difference between link and @import in CSS?
9. Please list how many ways (at least two ways) to clear float?
10. Block, inline and inlinke-block details comparison?
11. What is graceful degradation and progressive enhancement?
12. Talk about the problems caused by floating elements and how you solved them
13. What performance optimization methods do you have?
14. Why should CSS styles be initialized?
15. Explain float and how it works? Tips for clearing floats?
16. What types of CSS stylesheets can be classified according to the location of the web page?
17. What do you know about calibration in CSS?
18. Can you tell me the difference between EM and REM?
19. What is the use of box-sizing?
20. What is the difference between browser standard mode and weird mode?
21. What is Quirks mode and how does it differ from standard Standards mode?
22. What is your understanding of margin folding?
23. What is the difference between inline and block-level labels?
24. What are some ways to hide elements?
25. Why do I reset the default browser style? How do I reset the default browser style?
26. What is your understanding of BFC and IFC? (What it is, how it works, what it does)
27. Tell me your understanding of the use of position on a page.
28. How to solve the problem of multiple elements overlapping?
29. What are the layout methods?
30. Overflow: Hidden Does a new block-level formatting context form?
Chapter three front-end foundation
1. Talk about HTTP and HTTPS
2. TCP three-way handshake
3. Differences between TCP and UDP
4. Implementation and application of WebSocket
5.HTTP request mode, HEAD mode
6. How to achieve direct download after a picture URL access?
7. Talk about Web Quality
8. How many practical methods of BOM attribute object?
9. Talk about the HTML5 Drag API
10. Say something about HTTP2.0
11. Add the 400 and 401 and 403 status codes
12. The reason why fetch sent two requests
13.Cookie, sessionStorage, localStorage
14. Talk about Web workers
15. Understanding of HTML semantic tags
16. What is iframe? What are the disadvantages?
17. A Doctype? How to distinguish strict mode from promiscuous mode? What do they mean?
18. How does Cookie defend against XSS attacks
19. The difference between cookies and sessions
20. In a sentence
21. Talk about viewPort and mobile layout
22. Click has 300ms delay on ios, why and how to solve it?
23. The addEventListener parameters
24. Cookie sessionStorage localStorage difference
25. The cookie session
26. This section describes the status codes returned by HTTP
27. HTTP common request headers
28. Strong, negotiated cache
29.HTTP status codes say what you know
30. About 304
31. When to use strong cache or negotiated cache
32. Front-end optimization
33. Difference between GET and POST
34.301 and 302
35. How to draw a triangle
36. Status codes 304 and 200
37. Talk about browser caching
38. New elements for HTML5
39. Type a URL into the address bar, and what happens when the page displays?
40. Cookie and session, localStorage and sessionStorage
41. Common HTTP headers
42. HTTP2.0 features
43. What are the values of cache-control
44. Which two trees do browsers generate when they generate a page?
45. CSRF and XSS network attack and defense
46. What do you think of the performance of your website
47. Introduction to HTTP protocol (Features)
48. Talk about the cognition of cookies and Session. What are the limitations of cookies?
49. Describe XSS and CRSF attacks? Defense methods?
50. Do you know 304? When do I use 304?
51. Which request headers are specific to caching
52. The difference between cookies and sessions
53. What fields can be set in the cookie
54. What are the encoding methods of cookies?
Since you have seen the diagram HTTP, please answer the difference between 200 and 304
56. In addition to cookies, what other storage methods? Tell me the difference between cookie and localStorage
57. Browser input url to page rendering process
58. Are you using HTML5 and CSS3 a lot? Are you aware of their new properties? Have you ever used it in a project?
59. HTTP common request methods
60. Difference between GET and POST
61. Say the status code 302,301,304
62. Web performance optimization
63. Browser caching mechanism
64. Post is different from GET
65. Talk about the CSS box model
66. Draw a 0.5px line
67. Difference between link tag and import tag
68. Difference between Transition and animation
69. The Flex layout
70.BFC (block-level formatting context for clear float, preventing margin overlap, etc.)
71. Vertical centralization
72. The difference between JS animation and CSS3 animation
73. Talk about block elements and row elements
74. Ellipsis of text for multi-line elements
75. The visibility = hidden, opacity = 0, display: none
76. Double margin overlap problem (margin folding)
77. The position attribute
78. Float clearance
79. A range of new features
80. What are the CSS selectors and their priorities
81. How do you make an element disappear
83. How to implement CSS animation
84. How to center an image in a container?
85. How to achieve vertical centering of elements
86. Overflow handling in CSS3
87. What is the display element of float
88. A method to hide an element on a page
89. The implementation of the three-column layout, write as much as possible, floating layout, the generation order of the three divs does not affect
90. What is BFC
91. The calc properties
92. I have a Width300, a Height300, how do I center it vertically and horizontally on the screen
Display: What is the difference between table and table itself
94. What are the values of the position property and their differences
95. Positioning method of Z-index
96. The CSS box model
97. What if you want to change the font color of a DOM element without operating on it itself?
98. Are you familiar with the new properties of CSS?
99. What is the most used CSS attribute?
100. The difference between line-height and height
101. Set the background color of an element. What areas will the background color fill?
102. Do you know the priority of an attribute selector and a pseudo-class selector
103. The difference between inline-block, inline and block; Why img is inline and can set width and height
Create a coin rotation effect with CSS
105. Do you know about redraw and reorder, how to reduce redraw and reorder, and what are the ways to get documents out of the document stream
106. Draw cubes and triangles in CSS
107. The principle of overflow
108. Method of clearing float
109. The grammar and basic uses of box-sizing
110. What are some ways to make an element disappear?
111. Both nested divs and positions are absolute. The child div sets the top attribute relative to the parent element
112. Talk about the box model
113.display
114. How do I hide an element
115. Difference between display: None and Visibilty: Hidden
116. Relative and Absolute layout, position: Relative and Obsolute
117. The flex layout
118. Difference between block, inline, inline-block
119. Common selectors for CSS
120. The CSS layout
121. The CSS positioning
122. Relative positioning rules
123. Vertical center
124. What’s in the CSS preprocessor
Error in the length of get request parameters
126. Add cache differences between GET and POST requests
127. Talk about closures
128. Talk about class creation and inheritance
129. How to solve asynchronous callback hell
130. Talk about the flow of events in the front end
131. How do I bubble events first and then catch them
132. Talk about event delegation
133. Talk about lazy loading and preloading of images
134. Difference between mouseover and MouseEnter
What does the new operator of 135.js do
136. change the pointer to this inside a function (bind, apply, call)
137. The various location of js, such as clientHeight scrollHeight, offsetHeight, as well as the scrollTop, offsetTop, what is the difference between clientTop?
138.js drag function implementation
139. Asynchronous loading of JS methods
140.Ajax solves browser caching problems
141. Js throttling and anti-shake
142. Garbage collection mechanism in JS
143. What does Eval do
144. How to understand front-end modularity
145. Talk about Commonjs, AMD and CMD
146. Simple implementation of object deep cloning
147. Implement a once function, passing function arguments only once
148. Wrap native Ajax as a promise
149.js listens for object property changes
150. How do I implement a private variable that can be accessed using getName but not directly
151. The difference between == and ===, and Object.is
152. Differences between setTimeout, setInterval, and requestAnimationFrame
153. Implement a two-column contour layout
154. Implement a bind function yourself
155. Implement setInterval with setTimeout
156. Order of code execution
157. How to achieve sleep (ES5 or ES6)
158. Simply fulfill a promise
159. What is Function. Proto (getPrototypeOf)?
160. Implement deep clone of all objects in JS (wrapper object, Date object, re object)
161. Simply implement the Events module of Node
162 This in the arrow function points to an example
163. Js Determines the type
164. Array common methods
165. Array deduplication
166. What are closures for
167. Practical application of the event broker in the capture phase
168. Remove Spaces at the beginning and end of strings
169. Performance optimization
170. Can you talk about the language features of JS
171. How to determine an array
172. When you say typeof, can you add a constraint condition to reach the judgment condition
173.js implementation across domains
Js basic data type
175.js deep copy an implementation of an element
176. ES6set can be array deduplicated
177. Cross-domain principle
178. What are the rules for comparing values of different data types and how they are converted
179. Null == undefined
180. What does this point to
181. Suspended dead zone
184. There is a game called Flappy Bird, which is a Bird flying in front of endless desert, with steel pipes constantly growing up and down, and you have to avoid them. Then, Xiao Ming always gets stuck or even crashes when playing this game. Tell the reasons (3-5) and the solutions (3-5).
185. Write code that meets the following criteria:
186. What is load on Demand
187. What is the Virtual DOM
188. What is webpack for
189. Advantages and disadvantages of Ant-Design
Several ways to implement inheritance in 190.js
191. Write a function that prints 1 in the first second and 2 in the second
192. The lifecycle of a VUE
193. A brief introduction to symbol
194. What is event listening
195. Introduce promise and its underlying implementation
196. Bootstrap method for clearing floats
197. Tell us the difference between C++,Java, and JavaScript
198. Js Prototype Chain, what’s at the top of the prototype chain? What is the prototype of Object? What is the prototype of Object? The method of deleting duplicate data in array prototype chain is realized
199. What is a JS closure? What does it do, write a singleton with a closure
The use of 200. Promise + Generator + Async
201. Event delegation and bubbling principle
202. Write a function that converts an underscore name to a camel name
203. Difference and implementation of shallow copy
204. The difference between string startWith and indexof
205.js String to number method
What is block-level scope? How to implement block-level scope using ES5 method (execute function immediately)
207. Features of ES6 arrow functions
208. Execution order of setTimeout and Promise
209. Have you learned about the event model? What is the difference between DOM0 level and DOM2 level
210. How to debug JS at ordinary times
211.JS basic datatype, the difference between basic datatype and reference datatype, NaN is the abbreviation of what, JS scope type, undefined==null return result is what, undefined and null is the difference between what, write a function to determine the type of variable
212.setTimeout(fn,100); How does 100 milliseconds weigh
213.JS garbage collection mechanism
214. Write a newBind function to complete the bind function
215. How to obtain an attribute on an Object: for example, through object.key ()
216. A quick word on some of the new ES6 features
217. What do call and apply do?
218. Know about event agents and what are the benefits of doing so
219. Given the following code, what is the output? The reason?
220. Given two constructors A and B, how can A inherit from B?
221. What if you already have three promises, A, B, and C, that you want to implement sequentially?
Do you know private and public
223. Basic JS
224. How to use async and await?
225. Know the grammar of ES6 and ES7
226. Relation between promise and await/async
The data type of 227.js
228. Js loading process is blocked
229. Js object types, base object types, and reference object types
230. The implementation principle of JavaScript rotation? If you have two rounds on one page, how do you do that?
231. How to implement a calculation of how many weeks there are in a year?
232. Object-oriented inheritance
233. Objects with common reference types
234. The es6 commonly used
235.class
236. What is the difference between call and apply
237. Common es6 features
238. What is the difference between arrow functions and functions
The principle of the new operator
240.bind,apply,call
241. What is the difference between bind and apply
242. Promise
243. Deep copy of assign
244. Say promise, what if there is no promise
245.arguments
246. Arrow function gets arguments
247.Promise
248. Event broker
249.Eventloop
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Chapter four front-end core
1. The disadvantage of the json
2. Cross domain (JSONP, Ajax)
3. How to achieve cross-domain
4. What is dom?
5. What are the APIS for dom
6. State returned by Ajax
7. Implement an Ajax
8. How do I implement Ajax requests? Suppose I have multiple requests and I need to execute them all at once in some order? How do I handle Ajax across domains
9. How to implement an Ajax request? What do I need to do if I want to issue two ajax in sequence?
10. What are the advantages and disadvantages of Fetch over Ajax?
11. The relationship between mobile applications and Web applications
12. Do you know PWA
13. Have you ever made a mobile terminal
14. Do you know the Touch event
Chapter 5 Advanced front end
1. Front-end testing
2. Formulation of interface documents
3. Webpack vs. GulP (modularity vs. stream)
4. The story
5. Common methods in redux
6. AngularJs differs from React
7. Vue bidirectional binding principle
Vue React AngularJS jquery
9. Node’s event methods
10. What scenarios are suitable for node features
11. You use Express. Talk about Express
12. Promise states have those
13. What are the methods for removing the first element of an array?
Chapter 6 Mobile terminal development
1. React
React Single data flow
React life cycle Indicates the life cycle of the React function and the React component
React and Vue react and Vue react
5. Component communication of reactJs
React virtual DOM 6. How does the React virtual DOM compare
7. React is used in the project. Why do you choose React and what are its benefits
8. How do I get the real DOM
9. React
React lifecycle functions
11. The process after setState
React High-order components know?
13.React lifecycle
14. Tell me what you understand about React
15. What does the React component use to determine whether to refresh
Chapter 7 Computer fundamentals
1. Three-way handshake for TCP connection establishment
2. The principle of CDN
3. What the HTTP header contains. Common request methods (options, head, connect)
4. Request method head feature
5. What is the difference between the HTTP status code 301 and 302, 200 and 304
6.OSI seven-layer model
7. The difference between TCP and UDP, why three times shake hands and four times wave
8.HTTP caching mechanism
9. What is the difference between Websocket and Ajax? What are the application scenarios of Websocket
10.TCP/IP network model
11. Do you know what cross-domain mode is, what is the specific process of JSONP, how to achieve native JSONP encapsulation and optimization, and how to judge whether CORS should cross domain
12. How to generate tokens and how to pass them
13. Differences between operating system processes and threads
14. What is process thread
15. Those resources of the thread are shared and those resources are not shared
16. The difference between process and thread in operating system
17.Linux process query command, query port, kill process
18. What are the communication methods between processes?
19. Redis and mysql
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Chapter 8 Algorithms and data structures
1. Binary tree sequence traversal
2. The characteristics of B tree and the difference between B tree and B+ tree
3. The tail recursion
4. How to write a large factorial? What’s wrong with the recursive approach?
5. A way to turn a multidimensional array into a one-dimensional array
6. Know the sorting algorithm to say the principle of bubbling fast platoon
7. How does Heap sort work? Complexity?
8. Several common sorting algorithms, handwritten
9. Array deduplication, write as many methods as possible
10. If I have a large array of integers, how do I find the largest 10 digits
11. Know the common data structures in data structures
12. Find out how many occurrences of the KTH largest array in the array, such as array [1,2, 4, 4, 3, 5] the second largest number is 4, which occurs twice, so return 2
Merge two ordered arrays
14. Given a number, find the bit of that number in an sorted array (by quick lookup, binary lookup)……