Javascript-array Array Summary

1. Constructors New Array (); New Array (size); New Array (Ele0,ele1,ele2,..., Elen);ParametersSize: Sets the number of array elements, the length of the returned array is equal to size2. PropertiesLength: equals the ordinal of the last

JavaScript closures (Closure)

The scope of a variableTo understand the closure, you should first understand the JS special variable scope.There are two types of variables scoped to JS: Global variables and local variables.Global variables:var a = 999;function F1 () {alert (a);}

12 Very useful JavaScript tips

In this article, we will share 12 tips on JavaScript. These tips may help you solve some problems in your actual work.Using the !! operator to convert a Boolean valueSometimes we need to check whether a variable exists or checks if the value has a

Why string can have a method in JavaScript?

IntroductionAs we all know, JavaScript data types are divided into two major classes, primitive type (or original type) and reference type.The basic types of values are simple data segments that are stored in the stack memory and are accessed by

javascript--Array--sort Comparator

Because the original sort API is actually the first to compare the number of converted to a string and then compare, so it is not easy to useSo prepare to customize a comparer function:1 //Sort Principle--->sort (arr,compare)2 functionSort

JavaScript basic knowledge Blind spot summary--inheritance

In the primitive chain inheritance method, JavaScript is inherited by an instance of another class (actually, the entity that uses one constructor function overwrites another object's prototype). The following code:Twodshape.prototype = new Shape ();

Web pick-up reading notes----JavaScript language essence

Original link:Http:// values will be false (==false), respectively, false,null,undefined, ', 0,nan2.typeof has 6 values, which are ' number ', ' String ', ' Boolean ', ' undefined ', '

Javascript:date type

Create a Date object that uses the new operator followed by the constructor of date.var date = new Date();When the default constructor is called, the newly created date automatically obtains the current time and date. If you need to specify a date

Three ways JavaScript determines whether a picture is loaded

Three ways JavaScript determines whether a picture is loadedSometimes you need to get the size of the picture, which needs to be done after the picture is loaded. There are three ways to achieve this, as described below.First, the Load event

On JavaScript event Simulation

Events are used to describe a particular interesting moment in a Web page, and a well-known event is usually triggered when the user interacts with the browser, but in fact, JavaScript can trigger specific events at any time, and these events are

JavaScript arrays about 3

The first two sections say the basics of creating arrays, queue methods, sorting, and some operation methods, and this section is about iterative and merging methods.    Every () method & Some () methodThese two methods run the given function for

Learn JavaScript closures

The scope of a variableTo understand closures, you must first understand the special variable scope of JavaScript.The scope of a variable is nothing more than two kinds: global variables and local variables.The special point of the JavaScript

JavaScript Merge method reduce () and reduceright ()

ECMAScript 5 also added two methods for merging arrays: reduce () and reduceright (). Both of these methods iterate over all the items of an algebraic group and then build a value that is ultimately returned. where the reduce () method starts with

[JavaScript] Promise Simple Learning to use

Original address: callback functions nested too deep, parallel logic must be executed serially, a promise represents the end result of an asynchronous operation, the main way to interact with

JavaScript Arrays Array

Note: Length of 1.array is not read-only. You can move an item from the end of the array or add new items to the array. Look at the following example:var colors = ["Red", "yellow", "blue"];Colors.length = 2; (colors[2]);Results:

JavaScript Basics (iii) object condition judgment

A JavaScript object is an unordered collection data type that consists of a number of key pairs.var Guagua = {Name: ' Melon ',birth:1988,School: ' The Middle school ',height:1.70,WEIGHT:65,Score:null};JavaScript with a {...} Represents an object in

JavaScript Shallow clone and deep clone

First, shallow cloning1. Cloning of basic data type (assigned value)var a = 1; var b =//1//1a = 2//2 // 1When you assign a value to another variable, the value of that variable is not affected when it is changed.2. Array cloningIf we take the basic

Multi-level indicator scoring form automatically creates JavaScript code parsing

In order to explain the design of automatic scoring table based on multi-level indicators, as well as related indicators assessment scoring business, wrote the demo code for developers to reference, mainly related to table dynamic operation

How to use JavaScript and regular expressions for data validation

Original link: Enterprise Internet technology CommunityWith the advantage of client-side JavaScript, regular expressions in JavaScript can simplify the work of data validation, and below share with you how to use JavaScript and regular expressions

The idea of JavaScript programming with light pull

First, object-oriented-ood Although JS object-oriented programming idea has been talk about, but for the sake of the integrity of the article, I still add it in, try to speak in a different way (although there is no egg different).1, object-oriented,

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