JavaScript function Direct quantity (function () {}) _ Basics

What does the syntax mean (function () {}) () The following example: Reference How does that explain this? You should remember that. var a=function () {} So how do you run a? So that's a () Same reason. We don't save it through a variable. It

Javascript string byte length calculation function code and efficiency analysis (for VS Regular) _ Regular expressions

Let's take a look at two pieces of code that detect the byte length of a string, respectively, with a For loop and a regular expression: The For loop detects a string's byte length method one: Copy Code code as follows: var lenfor =

JavaScript IndexOf method, LastIndexOf method and substring Method _ basics

The IndexOf () method returns the location of the first occurrence of a specified string value in a string. Grammar Stringobject.indexof (Searchvalue,fromindex) Parameter description Searchvalue required. A string value that requires

The use of the Var keyword in javascript-basic knowledge

Roledeclaring a function, such as declaring a variable.Grammar  var c = 1; Omit Varin JavaScript, if you omit the var keyword and assign it directly, the variable is a global variable, even if it is defined in a function.

JavaScript variable Scope full resolution _ Basics

The scope of a variable is the region in the program that defines the variable.Let's take a look at an example: /* Code 1 * * var scope = "global"; function Checkscope () { var scope = ' local '; function Childcheck () { var scope = '

A deep understanding of the hoisting mechanism in JavaScript-basic knowledge

Hoisting mechanism The JavaScript variable declaration has a hoisting mechanism that, when executed, promotes the declaration of all variables to the front of the current scope. Read a piece of code first var v = "Hello"; (function () {

Guide to programming using the AMPLIFYJS component in conjunction with JavaScript _ basics

The role of event distribution The easiest thing to do when adding a variety of interactivity to a page is to bind the event to the page element, and then in the event handler, do what we want to do. It's like this code: Element.onclick =

JavaScript to determine whether two strings are equal to the method _ basics

First convert the user's input value to uppercase (or lowercase), and then compare: var name = Document.form1.txtUserName.value.toLowerCase (); if (name = = "Urname") { //statements go to here. } JavaScript

Basic knowledge of string concatenation in JavaScript

Very simply, "add" two strings with a "+": var longstring = "One Piece" + "plus one more piece."; To accumulate more than one string as a string, you can also use the "+ =" Operator: var result = ""; result =

Use Requirejs in JavaScript applications to implement deferred loading _ basics

Both simple and complex web applications are made up of HTML, JavaScript, and CSS files. Developers typically use a third-party JavaScript framework such as jquery, knockout, underscore, etc. to improve development speed. Because these JavaScript

JavaScript Basic Concepts Elementary Tutorial Forum Posted Learning Records _ Basics

1. About this object Copy Code code as follows: View Plaincopy to Clipboardprint? var obj1=new Object (); var obj2=new Object (); Add attribute p to all two objects, equal to 1 and 2 respectively Obj1.p=1; obj2.p=2;

JavaScript Basics Quiz Four Basics

Second, enhance the navigation function 1. Links in drop-down menu (links in Select menu) Q: How do I implement a link to a different page in the Drop-down menu? a: To create a drop-down menu as shown:Select a pageJavaScript

JavaScript Getting Started learning Seventh JS Dom instance operation 1th/2 Page _ Basics

Speaking directly from the method: 1, delete the node. RemoveChild (): a b c If you do not know what the parent node of the node you want to delete is? You can use the ParentNode property. Like what: a b c 2, replace the node.

JavaScript getelementsbyname () Usage Description _ Basics

We look at: oele= DOCUMENT.ALL.AAA//There is a AAA object here, but we do not know how long it is now, so there is no way to operate on it. Therefore, we have to do the process of judging length first. if (oele.length) {}else{}; In both cases, the

JavaScript error-prone knowledge point finishing _javascript skills

Objective This article is my Learning JavaScript process of collection and collation of some error-prone knowledge points, this paper introduces and explains the 6 aspects of variable scope, type comparison, this point, function parameter, closure

JavaScript Best Practices: help you improve code quality _JAVASCRIPT skills

Learning something new every day can put a rational person on the road to greatness. As a developer, continuous learning of new things is part of our work, whether these new things come from positive learning experience. In this tutorial, I'll

JavaScript Computing Cartesian Product example detailed _javascript skills

JavaScript implements Cartesian product Note: The set mentioned in this article refers to a mathematical set, not a set in ES6. The whole idea is as follows: The user passes in a two-dimensional array, each of which is a set of Cartesian

A brief talk on JavaScript constructor and instantiation Object _ basic knowledge

Preface --speak in front I think there are a lot of beginner friends who used to have little access to the background programming language, like me, confused a series of "nouns" in JavaScript. Seems to know what to say, but the understanding is

Explain the exception handling method in JavaScript _ basics

There are three kinds of programming errors: (1) syntax errors and (2) Run-time error (3) logic errors:syntax error: Syntax errors, also known as parsing errors, are performed at compile time in a traditional programming language and appear in

Tutorial Basics for using the logarithmic Math.log () method in JavaScript

This method returns the natural logarithm of a number (the base is e). If the value of the number is negative, the return value is always nan.Grammar Math.log (x); The following are the details of the parameters: X: a number.

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