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Learning to operate DOM DOM (Document Object Model) is a set of technical specifications formulated by W3C. It is a Web standard used to describe how JavaScript scripts interact with HTML or XML documents. DOM stipulates that the whole document is a document node, each element is an element node, the text contained in the element is a text no ...

catalogue Introduction to package First, let's briefly understand why packages are needed: Package classification: Package specification (basic): Package building steps:   Preliminary preparation:   Release package: Delete package: expand: Introduction to package First, let's briefly understand why packages are needed: Be ...

What is a package? Third-party modules in Node.js are also called packages Why do I need a bag? Because the built-in modules of Node.js provide only a few underlying API s, project development based on built-in modules is inefficient Packages are encapsulated based on built-in modules, providing a more advanced and convenient API, greatly ...

redux as we all know, it is the react Management Library of the third party. It is difficult for many people to make complaints about it and has to use it. I recently found that most of the functions of redux can be implemented only with react official hooks! It is easier to use than redux, and the amount of code is less. I wrote a complete dem ...

1, v-for 1. Update monitoring In general, changes in data will lead to v-for update, but in some cases, such as array method filter, it will return a new array, or directly change the value of the array in a literal way, which will not lead to v-for update. In such cases, reassignment or this.$set() or Vue.set() methods can be used // v-for ...

npm packages are updated very quickly in order to update projects or global dependencies to the latest version. The traditional method is to update one by one, such as updating react to the latest version. The command is as follows: # npm npm i --save react@latest # yarn yarn add react@latest Copy code yarn is a new generation of js package ...

JS What are basic data types in JS? What is a reference data type? difference? Basic data types (stored on the stack): number, string, Boolean, undefined, null Symbol(es6 new) Reference data type (stored in the heap and reference address of data stored in the stack): object, array, function, date, RegExp How many ways to judge the data ty ...

Mailbox 163 The alarm notification can be sent by mail. Then, in the previous document, we configured the sending email alarm method. 1. Set 163 mailbox To send mail, you need an smtp mail server. First, you need to set Netease mailbox. First log in to mailbox 163 and enter the mailbox center settings. Then start POP3/SMTP service, where yo ...

(1) let and const 1.let let defines a variable. A variable cannot be defined again, but its value can be changed Code: let name = 'zhangsan'; name = 'lisi'; console.log(name); // lisi let name = 'wangwu'; // Define again, and an error is reported: Identifier 'name' has already been declared Has block level scope. (i.e. braces) Code: ...

1.JS is single threaded    The code in JS is serial,   The previous execution is not completed, and the later cannot be executed 2. Execution sequence The program will execute all synchronization codes from top to bottomIf asynchronous code is encountered during execution, the asynchronous code will be placed in the event ...