99 front-end basic interview questions

The main content includes HTML, CSS, JavaScript, browser, performance optimization, etc., need to be able to click to get the PDF document!

  1. How do you understand the semantics of HTML structures
  2. Talk about the title and Alt attributes
  3. What are the new features and elements removed from Html5
  4. What does Label do? How does it work?
  5. How do browsers manage and load Html5 offline storage resources
  6. What are the disadvantages of iframe?
  7. HTML W3C standard
  8. Doctype? How to distinguish strict mode from promiscuous mode? What do they mean?
  9. What are HTML global attributes
  10. The content property of a viewport
  11. Meta related
  12. What are the advantages of div+ CSS over the Table layout
  13. Outline the difference between SRC and href
  14. Know the web page production will use the picture format
  15. How to embed audio and video in HTML5 pages?
  16. Horizontal middle method
  17. Vertical center method
  18. The difference between link and @import
  19. Three-column layout (middle fixed adaptive width on both sides)
  20. What does the BFC do
  21. Several ways to clear floats
  22. What’s new in CSS3
  23. Css3 added pseudo class – pseudo element
  24. Why do I initialize CSS styles
  25. IE box model, W3C box model

  1. Please explain the Flexbox (flexible box layout model) of CSS3 and how it applies
  2. Display: Inline-block when a gap is not displayed?
  3. Does the inline element float:left become a block-level element?
  4. If you need to write animation manually, what is the minimum time interval you think, and why?
  5. Display: When does inline-block display a gap?
  6. CSS weights and calculation rules
  7. What is Sass, LESS? Why do people use them?
  8. Stylus, Sass, less difference
  9. What is the difference between rGBA () and opacity?
  10. The difference between PX and EM
  11. Use CSS to achieve a continuous animation effect
  12. Rearrange and redraw
  13. What circumstances trigger rearrangement and redraw?
  14. A few basic JavaScript specifications
  15. closure
  16. The variable object
  17. scope
  18. Explain your understanding of scope chains
  19. JavaScript prototype, prototype chain? What are the characteristics?
  20. What is event delegation
  21. The creation of a class
  22. How is inheritance implemented?
  23. Talk about understanding This object
  24. The event model
  25. What exactly does the new operator do?

  1. Ajax principle
  2. Ajax solves browser caching problems
  3. How to solve cross-domain problems?
  4. Share your understanding of AMD and Commonjs
  5. The seven basic data types of js
  6. This section describes the built-in objects in JS
  7. JS which methods define objects
  8. What do you think is good about jQuery source code
  9. Null, undefined difference
  10. Talk about your understanding of ES6
  11. Object-oriented programming ideas
  12. How to determine an array from JS
  13. The implementation of asynchronous programming
  14. Know the direction of native Javascript
  15. Sort quickly scrambles arrays
  16. Array deduplication
  17. JS native drag node
  18. Deep copy, shallow copy
  19. Throttling stabilization
  20. Variable ascension
  21. Garbage collection mechanism in JS
  22. How to understand front-end modularity
  23. Js single-threaded
  24. Tell me about the event loop
  25. Describe this

  1. Ajax, AXIos, fetch difference
  2. How the browser stores it
  3. Browser kernel understanding
  4. HTTP request scenario
  5. The HTTP status code
  6. What happens when you enter the URL from the browser address bar?
  7. Talk about the pros and cons of cookies
  8. Cookies, sessionStorage and localStorage
  9. Browser cache
  10. Steps for browser rendering
  11. The difference between GET and POST requests
  12. What is the reflow
  13. When will reflow occur?
  14. Reduce the performance impact of Reflow
  15. SEO optimization
  16. Server optimization
  17. CSS optimization
  18. Js aspects
  19. Webpack optimization point
  20. Load optimization
  21. Page rendering optimization
  22. Image optimization
  23. The script to optimize
  24. Why is it more efficient to use multiple domain names to store website resources?

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Finally (Interview tips)

Resume Content:

  • Personal information: name, contact number and email address.

  • Write more practical projects to accumulate experience, you can let HR feel rich experience. Even if you don’t have much to write about, don’t cheat and try to describe the project in detail. For example, what projects you have done, what technologies you have used, what problems you have encountered and how to solve them, these are the places where you should write clearly.

  • Keep your resume short, keep it under two pages, and make it clear what you value most.

Answer tips:

  • Try not to stop at the question, but to spread out the answer points, guide the interviewer to ask questions, show your skills. Note that the prerequisite for guidance is that you are really familiar with this area, otherwise you are opening a hole for yourself.

  • If you don’t understand what the interviewer is asking, it’s best to find out what the interviewer is trying to ask, rather than trying to answer the question without getting it right.

The interview summary

  • As soon as possible after the interview, jot down any questions you have and review the entire interview. For the questions involved, you can check the data to verify whether you are wrong. If you are wrong, you should fill up the knowledge loophole.