JavaScript

Directory The parsing and executing process of JS preprocessing phase Implementation phase Second, scope Block scope function scope Dynamic scopes Lexical scopes Three,

To facilitate operation of the base type value, ECMAScript provides 3 special reference types:Boolean, number, and String. These types are similar to other reference types, but also have special behaviors corresponding to their respective base types.

Since I have been learning programming, I have not been able to understand the difference between objects and arrays, in fact, this is a very brain problem, arrays and objects should be well differentiated, arrays used to store multiple values in a

In JavaScript, functions are objects, and programs can manipulate them arbitrarily. For example, JavaScript can assign a function to a variable, or pass it as a parameter to other functions, and you can set properties on them or even invoke their

In daily development, the use of JS third-party libraries or plug-ins is required for agile development or faster meeting business needs.How to introduce JavaScript third-party libraries in Vue projectsGlobal variablesThe simplest way to add a

In the study of Liaoche predecessors of the JavaScript tutorial, encountered some points needing attention, so as a study notes listed, remind yourself to notice!If you have the need, welcome to visit the previous blog https://www.liaoxuefeng.com/

JavaScript Formatting of time dateFor the extension of date, the date is converted to the specified format of string//months (m), days (d), hours (h), minutes (m), seconds (s), quarter (q) can be used with 1-2 placeholders,//year (Y) can use 1-4

The purpose of this article is to ensure that you thoroughly understand JavaScript execution mechanism, if you do not understand this article, you can hit me.Whether you're a novice or a veteran of JavaScript, whether you're interviewing for a job

The file API is new to HTML5 and relies on file and FileReader, both of which are completed with the following code:varFileInput= document.getElementById (' Test-image-file '), Info= document.getElementById (' Test-file-info '), preview=

1 Character methodCharAt (): receives a parameter that returns the character at the given positioncharCodeAt (): receives a parameter that returns the character encoding of the specified position charactervar str = "Hello World"; alert (Str.charat (1

First we must understand JS has several data types?String number Boolean Object Null UndefinedMany other objects can be derived under Object objectssuch as function Date Math array, etc.I drew a picture of myself in a simple and rough way:Red

Links:JavaScript Promise: Introduction1. Chapter One chapter sequence download displayUse Array.reduce () and Promise.resolve () to concatenate the download and display of each chapter together as a whole.Download [Display] concatenation

JS argument detailedHTTPS://www.cnblogs.com/caoyc/p/5735299.htmlPersonal understanding: argument is a function parameter object, this object exists in every function, both tangible and actual argumentsActual parameter: Arguments.length parameter :

knowing your tools can greatly help you accomplish your task. Although JavaScript debugging is cumbersome, you can still solve these errors (errors) and problems (bugs) with as little time as possible with the skill (tricks).we'll list 14 debugging

Execution EnvironmentDefines the other data that a variable or function has access to, which determines their behavior. Each execution environment has one associated with it.Variable Object, all variables and functions defined in the environment are

JavaScript Basics (a) What is JavaScript Page-based scripting language Lightweight can be inserted into HTML Basically, all browsers support Completely different from Java LabelThe browser executes the script inside the

// ============ isarray ===============// // isarray function IsArray (value) { return Object.prototype.toString.call (value) = = "[Object] Array] "; } var arr = [1,2,3,4,5]; // IE8 and below are

Original: https://www.cnblogs.com/lidabo/archive/2012/01/05/2313481.htmlHttps://www.cnblogs.com/wdlhao/p/5743770.htmlPrototype is "a method of adding methods to objects of a class," and using the prototype property, you can dynamically add methods

Css/css3 implements vertical and horizontal center of unknown width and height elements, csscss3 In fact, in some common la s, it is often necessary to realize vertical and horizontal center of elements, the following describes the horizontal and

Note: "proficient in css" Chapter 2nd selector, comment, "proficient in css" Chapter 2ndChapter 2 selector, comment 1. You need to know the commonly used selectors (id selector, class selector, type selector, descendant selector, pseudo class