Null and undefined in JavaScript

The data types of JavaScript are broadly divided into two categories: primitive types and Object types. Where the original type includes numbers, strings, and Boolean values. In addition, there are two special primitive values in javascript: null

Nan error occurs after conversion of IE JavaScript string to date

Reference Blog: Internet Explorer, a Nan error occurs after the JavaScript string is converted to date, but there is no problem with other browsers.Therefore, the format of the string is

JavaScript variable assignment and parameter passing

Come to the conclusion first!Variable assignment:Base type: passed by value (that is, a copy is copied)Reference type: passed by reference (that is, a reference to the object is passed)Parameter passingBase type: passed by value (that is, a copy is

Two types of global objects/functions in JavaScript

The JavaScript mentioned here refers to the host environment in the browser environment. The first is the ECMAScript global object, and the second is the globally objects/functions under the Host Environment (host). One, core JavaScript built-in

Chrome Debugging JavaScript Scripts

As the complexity of JavaScript applications increases, developers need powerful debugging tools to help them quickly identify the cause of the problem and to fix it efficiently. Chrome DevTools offers a range of useful tools to make debugging

Explore the true meaning of JavaScript logical operators (and, OR)

More than half of the December, Winter is a wonderful season, the cold air forcing people to hide in a comfortable environment to live. Winter will give a quiet and peaceful atmosphere, let people immersed in it, as if the end of an old stage, but

javascript-page Print square, various triangles and diamonds

A. SquareA) control in the first for loop, outputting a total of a few lines. Depending on the output one line at a time, a newline character will be output later ;b) control the output of several pentagram per row in the second for loop. In this

The scope and scope chain of JavaScript

ScopeScope is the accessible scope of variables and functions, that is, scope controls the visibility and life cycle of variables and functions. It can be said that when variables and functions can be used, when they are destroyed, it is related to

Javascript 5 ways to filter delete before and after all spaces

First: cyclic check replacement//for the user to invokefunctionTrim (s) {returnTrimRight (Trimleft (s));} //Remove the left blankfunctionTrimleft (s) {if(s = =NULL) { return""; } varwhitespace =NewString ("\t\n\r"); varstr =NewString (s);

JavaScript Learning notes--3. Basic JavaScript Concepts

1. Everything in ECMAScript (variables, function names, and operators) is case-sensitive.2. Identifier: Refers to the name of a variable, function, property, or parameter of a function. The first character must be a letter, an underscore (_)

JavaScript Advanced Programming 3 Chapter III: Basic Concepts Chapter Content syntax data type flow control statement function

3.1 SyntaxECMAScript's syntax draws heavily on the syntax of C and other classes of C languages.3.1.1 Case Sensitive3.1.2 IdentifierA so-called identifier is a value variable, a function, the name of a property, or a function parameter. Identifiers

A few little exercises on the JavaScript algorithm--donyz

Dear friends, the following content is from my practice on the Freecodecamp, this is a good learning platform, here to share to everyone, the following question answer in the end of the article (the answer is written by myself, although all written,

JavaScript function calls the various methods!!

In JavaScript, there are 4 ways to call:(1) Basic function call(2) method invocation(3) Constructor call(4) calls via call () and apply ()1. Basic function callsNormal function call patterns, such as:JavaScript Code? 1234

Section 109th, JavaScript Object-oriented and prototype

JavaScript Object-oriented and prototypeLearning Essentials:1. Learning conditions2. Create an Object3. Prototypes4. InheritanceECMAScript has two development modes: 1. Functional (procedural), 2. Object-oriented (OOP). An object-oriented language

Object oriented JavaScript Advanced programming notes

Speaking of object-oriented, most programmers first think of classes. Classes allow you to create many instances or objects that have common properties and methods. But JavaScript doesn't have a class concept, and almost everything in JavaScript is

JavaScript series article: Automatic type Conversion-cont.

In the previous article, we explained in detail the automatic type conversion in JavaScript, which was not covered by any of the conversion rules due to space limitations, and is ready to be explained in detail.The last time we talked about object

JavaScript Error Record variable definition elevation, this pointer pointing, operator precedence, prototype, inheritance, global variable pollution, object properties, and prototype attribute precedence

Original location All variable declarations (VAR) or declared functions will be promoted to the top of the current functionWith regard to function expressions, JS splits the code into two lines of code to execute

JavaScript using the For Loop Bulk register event does not correctly get the resolution of the index value

One problem today is that when you use the For loop to bulk register an event handler, and then finally get the index value of the current element through an event handler, it fails, looking at a code instance:Analysis : In the above code, when

JavaScript Common function collation

JavaScript functions:1. Disable the right mouse button menu code blockfunction Stop () {return false;} Document.oncontextmenu = stop; Disable right mouse button Document.ondragstart = stop; Prohibit drag Document.onselectstart = stop; Prohibit

Deep understanding of properties and features in JavaScript

deep understanding of properties and features in JavaScriptThe properties and attributes in JavaScript are two completely different concepts, and i'll take a closer look at the properties and features in javascript, based on what I've Learned. The

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