Recently contacted the front-end knowledge, in order to prepare for the job interview, the following is to sort out some common front-end interview questions, divided into several parts, respectively is HTML, CSS, JS, followed by some common tools of the interview knowledge, the body is as follows:

A HTML.

1. Required test: How do you understand HTML semantics?

Semantic HTML is to use the correct labels, paragraphs write p tags, the title is write h1 tags, the article is to write the article, video is video tag, etc., in a nutshell is to let the professional person to do professional things, let the front page development to use the right label, so clear and conducive to optimize the code structure, be professional!Copy the code

2. What does meta Viewport do?

<meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1, minimum-scale=1"

Among them:name: viewPort for mobile devices content: Defines viewport attributes width: indicates the width of the mobile device initial-scale: indicates the zoom ratio between the device and the viewport maximum and minimum: Maximum must be greater than or equal to a minimum. The meta tag tells the browser not to zoom when displaying on mobileCopy the code

3. The H5 is what

H5 stands for mobile pages, not HTML5, not a technology, but a standardCopy the code

2. The CSS

Native JS

1. The closure

What is a closure:

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Code:

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2. What are the differences between call,apply and bind?

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3.Promise has code:

PromiseIt is the unified solution of asynchronous problem in front-end domain at present!Copy the code

4.JS has three big mountains: this, prototype and AJAX

zhuanlan.zhihu.com/p/143408048

DOM

HTTP

Framework Vue

Frame the React

TypeScript

Webpack

security

. Other

1. Understanding the front end:

The front end is a doorCopy the code