In JavaScript, num = num | | 1 What are the pros and cons of this notation?

Syntax sugar, equivalent to if (!! num = = false) Num=1; Java-like num=null? 1:numThe following is an answer from a friend who knows:It's just a shorthand method. The advantage is shorter, but in fact the disadvantage is even greater.Do you know

JavaScript Learning record Day1

JavaScript Learning record Day1学习javascript JavaScript Learning record Day1 1. Quick Start 2. Programming tools 3. Syntax 4. Notes 5. Case What is Javascritps? JavaScript is a

Riyuerusuo, topsy-JavaScript date

First, Date ObjectThe source code that appears below can be codepen online view .1) Timestamp millisecond calculationThe Date object is based on the number of milliseconds from "1970-01-01 08:00:00" to the specified date, not "00:00:00".The day is

Extending the functionality of the JavaScript base object in Typescript

In recent work, take note: Suppose we need a function, the output of a number such as 10000 to the following string format "10,000", generally write a method, then I would like to more convenient, directly add a format method to the # type, For

JavaScript data structures and algorithms-two fork tree (insert node, build two fork tree)

JavaScript data structures and algorithms-inserting nodes, generating two-fork treesIn a binary tree, a relatively small value is saved on the left node, and a larger value is saved in the right node/** Binary tree, the relatively small value is

"JavaScript" $.extend use and source research

Recently wrote more JS object-oriented programming, with $.extend write inheritance is very handy. However, several problems were found in the use of the process. 1. Deep copy $.extend is a shallow copy by default, which means that

Whether the function parameter is a value pass or a reference pass in Javascript

ObjectiveThis problem actually puzzled me for a long time, but in the actual use always muddle through, do not want to go deep. Because of this attitude, in the process of learning Javascript, the level has been out of half a bucket of water state,

Callback Hell--javascript Async Programming Guide

Original:Callback HellWhat is "Callback Hell"?In JavaScript, we often use callbacks to implement asynchronous logic, and once the nesting level is more, the code structure becomes very intuitive and ends up looking like this:Fs.readdir

JavaScript Basics Article

All data types:Basic data type:UndefinedNumberBooleanNullStringComplex data types:Object①undefined:>>> declared but uninitialized variable: typeof-undefinedAler-UndefinedNon-declared variable: typeof-undefinedAlert-Error②null:>>>typeof a variable

Full stack JavaScript road (19) HTML5 Inserting HTML tags (i) InnerHTML and outerhtml

You need to insert a large number of HTML tags into the document. The DOM operation is cumbersome, and you will not only create a series of nodes, but also carefully link them in order.With HTML tag insertion technology, you can insert HTML code

JavaScript Learning Summary (i) DOM Document Object model

I. Documentation (D)A Web page runs in a browser, and he is a document object.Ii. Objects (O)An "Object" is a self-contained collection of data. A variable associated with a particular object is called a property of this object, and a function

JavaScript base Split ("") splits a string into a character array

Town Field Poem:The Pure Heart sentiment wisdom language, does not have the world name and the benefit. Learn water under the hundred rivers, give up arrogant slow meaning.Learn to have a small return to feed root, willing to cast a conscience blog.

JavaScript base date (num) num creates a time object for millisecond values

Town Field Poem:The Pure Heart sentiment wisdom language, does not have the world name and the benefit. Learn water under the hundred rivers, give up arrogant slow meaning.Learn to have a small return to feed root, willing to cast a conscience blog.

JavaScript base math.abs (num) to find the absolute value of num

Town Field Poem:The Pure Heart sentiment wisdom language, does not have the world name and the benefit. Learn water under the hundred rivers, give up arrogant slow meaning.Learn to have a small return to feed root, willing to cast a conscience blog.

JavaScript base toFixed () converts a numeric value to a string and rounds it, preserving a decimal number of the specified digits

Town Field Poem:The Pure Heart sentiment wisdom language, does not have the world name and the benefit. Learn water under the hundred rivers, give up arrogant slow meaning.Learn to have a small return to feed root, willing to cast a conscience blog.

Interactive pathfinding of "JS" JavaScript and HTML DOM

JS HTML DOMThe entire DOM is the Document object module, which is the documentation objects model. In general, when a page is loaded, the browser creates a DOM of the current document internally. Just as the object created when parsing an XML file

Read the JavaScript authoritative guide (sixth Edition) Notes (chapter fifth)

StatementAn expression is a phrase in JavaScript, and the statement is a JavaScript whole sentence or command. Use a period to end to separate statements. An expression evaluates a value, but the statement is used to execute to make something happen.

javascript-Basic Articles <Script></script> basic use

1. Properties:1.1.async: Optional, indicates that the script is loaded immediately, but does not interfere with other actions on the page, such as downloading other scripts.Instance:   "UTF-8"> [email protected]163. com time: .-Geneva-

JavaScript's regular also has a single-line mode.

The regular expression was first implemented by Ken Thompson in his improved QED editor in 1970, the simplest meta-character in the regular "." At the time, the match is any character except for the line break: "." is a regular expression

Built-in objects for JavaScript

Built-in objects in JavaScript typically have datetime date () objects, arrays of Arra (), string strings.The Date object is generally used to get and modify the current datetime, etc., we first declare the Date object, and then call the function in

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