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1. Review of knowledge points Parent element: parent node Get style # getComputedStyle # ele Currentstyle (IE compatible) The difference between className # and classList className is a string and classList is an array className: sets or returns the class attribute of an element. It returns a string. If I want to delete or add and r ...

First, you need to understand what is Event Loop? Event Loop is an operating mechanism of computer system. JavaScript uses this mechanism to solve some problems caused by single thread operation. 1. Why is JavaScript single threaded? The single thread of JavaScript is related to its purpose. As a browser scripting language, JavaScript is ma ...

1. Entry function Portal on official website: https://jquery.com/jQuery file download: https://code.jquery.com/jquery-1.12.4.min.jsOfficial document portal: http://jquery.cuishifeng.cn/index.html Js native entry function: window.onload = function(){ }​Jq entry function: Abbreviation: $(function() {}) Standard: $(document) ready(function () ...

3. Return value of function If the return keyword is not written in the function, the function returns undefined by default <script> function f1(){ var a = 1; var b = 2; } var a = f1(); console.log(a); </script> If there is a return keyword in the function, the value after return is returned <script> function f ...

forEachno return valuevar a = [1,2,3,4,5] var b = a.forEach((item) => { item = item * 2 }) console.log(b) // undefinedCannot interrupt executionThe execution cannot be interrupted during forEach traversal. If you want to meet certain conditions, the traversal will be interrupted. Use the for loop.var arr = [1, 2, 3]; for (var i = 0; i & ...

Async keyword is used to declare asynchronous functions. await is used to change asynchronous code into synchronization in async functions and block code execution For those unfamiliar with promise and generator, you can take a step-by-step look at these articles Understanding and use of Promise (I) Understanding and use of Promise (II) Step b ...

The previous learning section introduced the use of some form contents - the previous cases basically used input. Next, learn the difference between controlled forms and uncontrolled forms, and learn the knowledge points of uncontrolled components through uncontrolled forms. Controlled forms refer to forms whose states are managed by React ...

1. javascript composition 3. Composition: 1 Basic grammar 2 bom 3. dom 1.1 ECMAScript (some syntax of js) ECMA:Organization, European Computer Association (standards) 1.2 BOM: Browser Object Model -- browser object model js script control browser The objects contained in bom are: bom contains dom How to say this -- Window means W ...

Section IV engineering construction of component library Reference video link: [I want to open source] personally taught by Huawei leaders, Vue DevUI open source guide 04: project initialization and jsx support for engineering construction of component library_ Beep beep beep_ bilibili Reference documents: [I want to open source] Vue DevUI op ...

Condition test The following programming paradigms can be clearly expressed: If X, then Y, else Z Today, modern JavaScript applications are highly dynamic and variable. Their state and DOM change over time. The problem with conditional testing is that it can only be used when the state is stable. In modern applications, it is often impo ...