CSS . 1 , box model 2 , Flex . 3 , CSS units . 4 , CSS selectors . 5 , BFC clear float 6 , laminated context 7 , common page layout 8 , in response layout . 9 , CSS pretreatment, post-treatment 10 , new features CSS3 animation transiton and related attributes animate and Translate . 11 , the value which the display 12, the adjacent two inline- why the node will block interval, what is the solution 13 is , the viewport Meta movable end fitting 14, CSS width adaptive to achieve 100% , width and height 16: 9 ratio of the rectangle 15 , the advantages and disadvantages rem layout 16 , draw a triangle 17 , a pixel border problem HTML 1 , semantic 2 , new features new label 3, The difference between the input and textarea 4 , with implementation of a div analog textarea 5 , the mobile device will ignore the method of identifying the page number to the telephone number of the JS . 1, the prototype / prototype chain / constructor / instance / inheritance 2 , there are several ways inheritance 3 , using a prototype implementation inheritance any shortcomings, how to solve . 4 , arguments . 5 , the data type judgment 6 scope chain, closures scope . 7 , Ajax native wording 8 , deep copy the object, shallow copy 9 picture lazy loading, preloaded 10 , implement page loading progress bar 11 , the this keyword 12 , functional programming 13 , implemented manually parseInt 14 , why there is homologous strategy 15 , how to determine whether two objects are equal 16 , the event model event delegates, proxy how to make the first event after the bubble capture 17, Onload event of the window and DOMContentLoaded 18, for ... in and for ... of iterations What is the difference 19 , function curried 20 , Call the Apply distinction, native to realize the bind Call, the Apply, and use the bind three differences: parameter may be an angle, bind rule (binding and displayed strong binding), operating efficiency, operation. 21 is, the async / the await 22 is , immediate execution of the function and usage scenarios 23, the design pattern (how to say requirements, applications, advantages and disadvantages) / single mode implemented Example 24 , which has the disadvantage iframes 25 , an array of problems arrays to re- array common method lookup array duplicates flat array by an array of specific values and the difference between ordering 26 , BOM attributes of the object method 27 , the server rendering 28 , garbage collection mechanism 29 , eventloop process and thread task queue 30 , how to quickly make a string has been turned into thousands of precision digital ES6 1 , the statement let, const 2 , destructuring assignment 3 , declare classes and inheritance: class, Extend . 4 , using Promise and implementation . 5 , Generator (asynchronous programming, the yield, Next (), the await, the async) . 6 , arrow function this point the problem, expand operator 7 , map and set have not been used, how to implement an array of deduplication, map data structure What are the advantages? 8, ES6 how compiled into ES5, css- Loader principle, the process 9 , ES6 ES5 turn into a common example of the use of es5 achieve es6 the class browser 1 , enter the url to the page showing the process of what happened? 2 , with the return redraw redraw (repaint): When change does not affect the layout of the style elements, the browser will use to redraw the elements to be updated, only this time due to the need to re-draw the UI pixel level, and therefore less wear and tear reflux (reflow): when the element size, structure, or trigger certain attributes, the browser will re-render the page, called reflux. In this case, the browser needs to go through re-calculation, the calculations also need to re-page layout, and therefore heavier operations. Operation will trigger reflux of: * the page is first rendered * browser window is resized * element size, location, content change *Elements change the font size * Add or remove visible dom element * activate CSS pseudo-classes (such as hover ::) * query certain properties or calling certain methods * clientWidth, clientHeight, clientTop, clientLeft * offsetWidth, offsetHeight, offsetTop, the offsetLeft * scrollWidth, scrollHeight, scrollTop, scrollLeft * getComputedStyle () * getBoundingClientRect () * scrollTo () reflux triggers must redraw, redraw necessarily trigger reflux. Redraw overhead smaller, higher reflux price. 3 , anti-shake with the throttle . 4 , Cookies, the session, the sessionStorage, localStorage . 5 , the rendering engine server to the network 1 , a common status code 2 , buffer 200 is the From Cache and OK 200 is 400, 401403 status code representing what browser cache 3 , the cookie, the session, token 4 , the front end persistent way, the difference between 5 , the DNS is how to resolve the 6 , CDN 7 related protocols, computer networks 8, http / https / http2 .0 9 , the difference between GET POST 10 , ajax, Axios library 11 , tcp three-way handshake, waving process four times 12 , the cross-domain 13 , front-end security XSS, CSRF 14 , the WebSocket 15, Keep-Http request alive you have to understand 16 , hierarchical network 17 , instant messaging, in addition to Ajax and the WebSocket 18 , modular, CommonJS, ES6, cmd, AMD Vue 1 , VUE solve the problem 2 , MVVM understanding of 3 , how to implement a custom components, the different components of how to communicate between? 4 , nextTick 5 , the life cycle 6 , the principle of virtual dom 7 , two-way binding principles? Data hijacking? 8 , components of the communication parent -> child child -> parent non Sons assembly . 9 , the Proxy defineProperty advantages compared to the 10 , Watch computed difference . 11 , Virtual DOM principles to achieve 12 is, vue- Router (the hash, the HTML5 new pushState Leaflet application, how to achieve its routing functions --- routing principle VUE - Router how do users log on rights such as how you implement nested route in the project 13 , vuex understanding of front-end performance optimization too many pages DOM node, what will happen? how to optimize? how do performance monitoring SEO semantic and this has not been asked micro letter applet micro-channel program and h5 small difference, if there is weex development experience, you may add weex git some basic commands packaging tools WebPACK 1 , packing principle 2 , packing plug 3 , WebPACK hot update principle 4 , to optimize the speed of constructing algorithms 1 , sorting algorithm 2 , dynamic programming, see knapsack problem 3 , the binary tree 4 , issue stations (greedy algorithm) 5 dichotomy 6 , the binary tree traversal 7 , single chain reversal 8 , 1000 to take the inside of the prime numbers 9, and to find the array two elements of a given value, such as: [1, 2, 3, 4, 5 ] and to identify the two elements 6. 10 , the linear sequential storage structure and chain storage structure What is the difference? Advantages and disadvantages of the mobile terminal 1 , an adaptive 2 , PWA . 3 , the mobile terminal gesture additional questions 1 , infinite scroll program 2 , how to deal with compatibility issues 3You encountered the most difficult question is what 4 , ES6 class differences and contact with ES5 function 5 , VUE how to listen array 6 , you wrote webpack loader 7, login mechanism ponder the micro-letter web version