In-depth understanding of JavaScript prototypes and Closures (12)--closures

The official definition of a closure is a function that has permission to access variables in another function scope.Closures are used in two ways: functions as return values, functions as argumentsFirst: function as return valueIn the above code,

Deep understanding of JavaScript prototypes and Closures (5)--instanceof

For value types, you can use TypeOf to judge, but typeof the reference type when the return value is only object/function, do not know exactly which one. The instance will be used at this time. For example, F1 is created by the Foo function, but why

JavaScript standard Reference Tutorial (Alpha) Notes

JavaScript Standard Reference Tutorial (Alpha) Notes N--: Use n again to execute n=n-1;--N: Execute n=n-1 before using n;The 2.1.5 chunk ({}) var does not constitute a separate scope for the

JavaScript error-prone knowledge point collation

1. Variable Scopevar a = 1; function Test () { var a = 2; // 2 }test ();The above function scope declares and assigns a, and above the console, so follows the nearest principle output a equals 2.var a = 1; function test2 () { // undefined

JavaScript-javascript DOM Programming Art (2nd edition)

/* Progressive enhancement smooth degraded web page structure layer (structural layer): HTML presentation layer (presentation layer): CSS Behavior layer (behavior layer): JavaScript 1, using meaningful markup to construct the structure of the page;

Use JavaScript to iterate through

The push () method adds one or more elements to the end of the array and returns the new length.Each () method specifies the function to run for each matching element.The parseint () function parses a string and returns an integer.Use JavaScript to

JavaScript tab switch function (minimalist code)

1 DOCTYPE HTML>2 HTMLLang= "en">3 Scriptsrc= "Http://">Script>4 Head>5 MetaCharSet= "UTF-8">6 title>Boss Patriotictitle>7 style>8 Body{background:#ececec;margin:0;}9 #test{width:100%;Height:40px;background:#

JavaScript Usage Myths

1.JavaScript Usage Error1.1 Assignment operator Application errorIn a JavaScript program, if you use the equal sign (=) of the assignment operator in an IF condition statement, the correct method is to use the two equals sign (= =) of the comparison

JavaScript closures Detailed

First, what is anonymous functionCreate a function and assign it to the variable functionname, in which case the function created is the anonymous function. (function expression is an anonymous function)Second, closed package1. What is a closure?

JavaScript pre-compilation principle analysis

Today, I spent a lot of time reviewing scopes, precompilation, and so on.Looked very Doboven, turned over once read the book (as if many books did not say pre-compilation)found that they have learned very clearly, in fact, there are some mistaken

JavaScript Object-oriented (multiple ways to create objects)

Creating objectsFirst type: Object-basedvar New = ' My Name '=function() { returnthis. Name;}Second: The object literal way (a more clear Lookup object contains the properties and methods)var person = { ' My name ', +, function() {

Some basics of JavaScript one

1, the understanding of JSA, developed by Netscape (Netscape) b, which is a cross-platform scripting language C, applied to Web pages, to operate the browser and Web content D, JavaScript was originally designed to verify the correctness of HTML

The lexical structure of JavaScript

1. Character SetThe JavaScript program is written in Unicode (two-byte notation) character set.2. Case-sensitive  JavaScript is a case-sensitive language. HTML is case-insensitive, due to the fact that the two are closely related and differentiated.3

JavaScript authoritative Guide Reading notes-3rd chapter types, values and variables (1)

Have always had an idea, well read JS authoritative guide, easy for their own JS have a more comprehensive understanding. After all, I am not a computer professional born, although doing related industry work, but always feel that the master of the

JavaScript design mode (4)

Bridging modeWhen designing a Js API, you can use it to weaken the coupling between it and the classes and objects that use it.1. callback function for event listenerfunction Getbeerbyid(ID,Callback{ asyncrequest(' GET ', ' beer.uri?id= ' +Id,

Javascript-about for in and foreach

Js-for in: Used to traverse objects1 //traversing objects for in2 3 varOpts={name: ' Xiaofei ', Age: ' 28 years old ', Job: ' Web Front end engineer '}4 5 for(varKinchopts) {6 7Console.log (k + ': ' +Opts[k])8 9 }Ten //Name:xiaofei One //age:28

Webassembly is a silver bullet that solves JavaScript's ills?

Write in front"No silver Bullet" is a classic paper on software engineering published by Fred Brooks in 1987. The main argument of this paper is that there is no one technology or method that can increase the productivity of software engineering by 1

Implementation of the Copy button on the Clipboard/Web page by JavaScript copy content

JavaScript copy content to Clipboard/page Copy button implementation: Demo belowDOCTYPE HTML>HTML>Head>MetaCharSet= "Utf-8">title>Copy Content to Clipboardtitle>Script>functioncopy () {document.getElementById ("content"). Select ();//Select the

The garbage collection mechanism in JavaScript

What is JS garbage collection? (what)JavaScript also has an automatic garbage collection mechanism (gc:garbage Collection);Because memory content is extremely limited, the garbage collector periodically (periodically) finds variables that are not in

JavaScript namespace mode

ObjectiveA namespace can be considered a logical grouping of code under a unique identifier. Why does the concept of namespaces appear? Because the number of words available is too small, and different people write programs can not all variables are

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