JavaScript

There are 7 types of data:undefined(Not defined)null(empty),boolean(Boolean type)stringStringsymbol(symbol),numberDigitalobjectObjectNaming rulesVariableThe name of (a variable) can be a number, a letter, $ or a _ composition, but not a space or a

　　JS Variable Scope Features:The scope of a and JS variables is based on its unique scope chain.b, JavaScript does not have a block-level scope.c, the variables declared in the function are defined throughout the function.1. Scope Chain var rain = 1

First, background knowledgeBefore I introduce closures, I think it is necessary to introduce some background knowledge, such as the scope of variables, nested functions, garbage collection mechanism and so on.1. ScopeScope is the scope of the

Several special cases of function internal variables:1. Global variables and local variablesfunction internal variable declaration with var keyword:1 function Global () {2 var name = "Lilei" //variable declaration with VAR, still local

applebananacatJavaScript Getting Started case

Now the mobile is so popular, we can operate more on the mobile phone. It's also very necessary for a Web page to have some rich operational feel, right (if you just need click, then I'm not saying it ...) ~ ~ For example to achieve up and down,

Getboundingclientrect ()This method returns a rectangle object that contains four properties: Left, top, right, and bottom. Represents the distance between the edges of the element and the top and left sides of the page, respectively.var

Codewars Address: https://www.codewars.com/Welcome to discuss with you allBasic Exercises (1):My answer is:function Isisogram (str) { ifreturntrue; return str.tolowercase (). Split (""). Sort (). Every (function(item,index,array) { return Item!

InnerHTML: Gets the entire contents from the object's starting position to the terminating position, including the HTML tagInnerText: Gets the content from the start position to the terminating position, but removes the HTML tagWrite a code below to

The JavaScript engine is not an article-by-article execution of JavaScript code, but rather a fragment of code blocks to explain execution. The so-called code block is the code snippet separated by the tag.There are two stages in the entire code

1: Adding object properties dynamically var obj = new Object ();Console.log (Obj.username);Obj.username = "haha";Console.log (Obj.username);Undefinedhahadenoted by "[]". Written obj["username"] = "haha";var obj = new Object ();Console.log

Object.prototype.deepcopy=function () { var obj=arguments[0]| | {}; for (var i in this) { if (This.hasownproperty (i)) { if (Issimpleobject (This[i])) { obj[i]={}; This[i].deepcopy (Obj[i]);

1. VariablesDefine variables using the var keyword,function Test () { var 'one'; } Test (); alert (cc); // error not defined variable If you remove Var, it will pop up 11 ... This example can explain the use of global

ECMA-262 (E3) did not write the JSON concept to the standard, fortunately the concept of JSON in ECMA-262 (E5) was formally introduced, including the global JSON object and the Tojson method of date.1,eval way to parse, I am afraid this is the

What is the difference between onmouseover and hover in CSS? onmouseoverhover They are the same because:It is triggered when the mouse is down.They are different because:Onmousemove is in javascript. It can trigger js commands, but hover cannot.

A picture teaches CSS3 reflection and css3 reflectionShareSample Image Before CSS3, to implement a reflection effect like a sample image, we can only process the image. After CSS3 came out, it became very simple to implement this effect, it can be

Exploring vue server rendering (SSR), vuessr Preface First, let's talk about server rendering. Simply put, the server parses and renders data and directly generates html fragments and returns them to the front-end. There are also many specific usage

Javascript implements random numbers, letter verification codes, and js random numbers. This article provides an example of how to implement a verification code for numbers and letters for your reference. The details are as follows: Verification

Webpack Command Execution parameters and webpack Parameters I. Overview The previous sections explain how to install and use webpack. config. the basic configuration of js, the name of webpack execution, and the use of the require method are unknown.

Describes the data communication instances between Vue components and vue Data Communication I recently used vue for projects and learned a lot, but sometimes I am patronizing projects, but I forget to find a time to sort out some of the latest new