preface

Is really 15 aspects of the front end of the test, the answer to the question document, the length of the reason only enumerated part of the topic, the complete version of the canClick here to see oh.

Summary of the knowledge content mastered by the front end

HTML/CSS

Understanding of web fidelity (structure/presentation/behavior), browser kernel, rendering principles, dependency management, compatibility, CSS syntax, hierarchy, common properties, layouts, selectors, box models, hacks, CSS preprocessor, Flexbox, CSS Modules, Document Flow, BFC, HTML5 (offline & storage &history, multimedia, WebGL, SVG, Cavas)

Javascript

Data Type, Operations, Objects, Inheritance, Closure, Scope, Event, Prototype, Regexp, JAON, AJAX, DOM, Memory Leaks, Cross-Domain, Aasynchronous Request, Template Engine, Modularity, Flux, Isomorphism, Algorithms, NodeJS, HTTP

other

Mainline MVVM, Hybrid App\React Native\Weex, TypeScript, Front-end Engineering, dependency management, performance optimization, reconstruction, SEO, UED, front-end technology selection, etc

Front end test questions to master

HTML

  • What does a DOCTYPE do?
  • The difference between Standard Mode and Weird Mode:
  • What are inline/block-level/empty elements?
  • What is your understanding of the browser kernel?
  • What are the cores of common browsers?
  • How does the browser manage and load HTML5’s offline storage resources?
  • What is the difference between cookies/sessionStorage and localStorage?
  • What are the new features of HTML5? How do you handle compatibility issues with new HTML5 tags? How do you distinguish between HTML and HTML5?
  • Describe your understanding of semantic HTML.

  • How does HTML5 offline caching work? Can you explain how it works? .

    CSS

  • ☆ Browser box model?
  • ☆ Clear floating way
  • What are the CSS selectors? Which attributes can be inherited?
  • What’s the difference between ::after/:after and ::before/:before?
  • CSS style priority calculation method:
  • ☆ What are the new features and pseudoclasses in CSS3?
  • Some advantages of less.
  • How to center div?
  • What are the values of Display? Explain their role
  • The value of the Position?
  • Flex layouts and common properties
  • Can you explain the flexbox model of CSS3 and the applicable scenarios?
  • CSS to create triangles?
  • Full screen product word layout?
  • What is the cause of the invisible gap between Li and Li?
  • Why initialize CSS styles?
  • The collapse property of the visibility property in CSS does not exist.

  • What does margin merge mean? .

    JS

  • What are the JS data types?
  • What are the built-in objects in JS?
  • What’s the difference between a stack and a heap?
  • Scopes and variable declarations in js are enhanced
  • How do I convert a type?
  • What are object-oriented programming and procedural programming, their similarities, differences, advantages and disadvantages
  • Object-Oriented Programming Ideas
  • How to explain the role of this in JS?
  • How to use this in js (classic) :
  • ☆ Talk about JS prototype and prototype chain
  • How do you know exactly when a variable is of array type?
  • ☆ What is the difference between call and apply?
  • What are the methods of inheritance?
  • ☆ What are closures? What do closures do?
  • Event agent (event delegate) :
  • The stages of the event
  • ☆ What phases does the new operator go through when creating an instance
  • How asynchronous programming is implemented
  • Knowledge of native JS
  • What are the methods of lazy loading in js?
  • Arrays sorted from small to large?

  • Sort the array from large to small, and then add the reverse() method to reverse the order…

    JQuery:

  • What do you think is the best way to write the jQuery or Zepto source code
  • How does jQuery work?
  • What is the object returned by the init method of jQuery.fn? Why do you want to return this?
  • How does jquery.extend differ from jquery.fn. Extend?
  • How does jQuery implement extend and how does it implement deep copy?
  • How is jQuery’s queue implemented? Where can queues be used?
  • JQuery bind (), live (), delegate (), on ()
  • JQuery An object can bind multiple events at the same time. How does this work?

  • Optimization for jQuery? .

    Data request related issues

  • What are the HTTP requests?
  • What are the HTTP status codes? Let me tell you what they mean
  • Please describe the difference between GET and POST
  • Error in the length of the GET request
  • The difference in caching between GET and POST requests
  • What’s the difference between HTTP and HTTPS? How to use it flexibly?
  • AJax is what? Why use Ajax?
  • Describe the Ajax process.
  • The pros and cons of Ajax?
  • XMLHttpRequest generic properties and methods
  • AJAX requests cross domain interfaces. How many requests are sent?
  • There are several ways to cross domains
  • What are the ways for web applications to actively push data from the server side?
  • How to realize the communication between multiple tabs in the browser? (ali)
  • How does WebSocket work with low browsers? (ali)
  • Detailed differences and pros and cons between FETCH, AJAX, and Axios:
  • What is Axios? How to use it? Describe the process of using it to implement the login function?

  • What’s the difference between XML and JSON? .

    Vue

  • What is the MVVM?
  • The difference between MVVM and MVC? How does it differ from other frameworks (jQuery)? Which scenarios are appropriate?
  • What are the two cores of Vue.js?
  • Passing values between VUE components
  • How to use custom components in Vue-CLI, and what problems have you encountered?
  • How does Vue implement load on demand with Webpack setup
  • The similarities and differences between the v-show and v-if instructions
  • How do I make CSS work only in the current component
  • What is the function of
    ?
  • Talk about the implementation of Keep-Alive and its caching strategy
  • Steps to introduce components in VUE
  • Common modifiers for Vue?
  • What are Vue’s computed properties?
  • Vue and other single-page applications and their advantages and disadvantages?
  • What is the function of the instruction v-el?
  • Steps to use the plug-in in Vue
  • Active-class is a property of which component?

  • Name at least 4 instructions in Vue and how to use them. .

    React

  • Use of props and state in React
  • How do React components communicate with each other?
  • Why does virtual DOM improve performance?
  • React Lifecycle Functions:
  • What periodic function is React performance optimization?
  • At what point in the life cycle should you make an Ajax request?
  • An overview of the event handling logic in React
  • How do I tell React that it should build the production version?
  • What happens after setState is called?
  • Principles and usage of setState by React
  • Why is setState asynchronous?
  • What does the second argument passed to the setState function do?
  • What does shouldComponentUpdate do and why is it so important?
  • What is the difference between a createElement and a cloneElement?
  • Why do we need to use the Children API provided by React instead of JS Map?
  • What is the difference between Element and Component in React?
  • Under what circumstances would you prefer to use a Class Component over a Functional Compone
  • What do refs do in React?

  • The diff algorithm? .

    WeChat applet

  • A brief description of the WeChat applet related file types?
  • How do you encapsulate the data request of WeChat applet?
  • What are the methods for passing values to parameters?
  • What methods have you used to improve the speed of WeChat applet applications?
  • Small program and native APP which good?
  • Briefly describe the principle of WeChat applet?
  • Analyze the advantages and disadvantages of WeChat applet
  • What is the difference between WeChat applet and H5?
  • How to solve the small program asynchronous request problem?
  • How is two-way binding for applets different from Vue
  • Small program WXSS and CSS what are the different places?
  • Small program associated with WeChat public number how to determine the uniqueness of the user?
  • What should I pay attention to when using WebView to load directly?
  • What problems do small programs encounter when calling the background interface?
  • Small program to write a custom component, to consider what?
  • Small program how to obtain user authorization information?
  • Add a Button button to the page and set the open-type property to getUserInfo.
  • How do applets share card information? .

Come on, let us all have the ability of the line with Dachang!