5 Rules of javascript--prototypes

Tag: URI has a console implicit BSP Java Log ext post1, all reference types (objects, arrays, functions), all have object attributes, can be freely extended properties (except null)var obj ==; var arr ==; function = 100; 2. All reference types

Conversion of radians and angles in JavaScript

弧度 = 角度 * Math.PI / 180角度 = 弧度 * 180 / Math.PI In the JavaScript Math object:The sin () method returns the sine of a number.The tan () method returns a number that represents the tangent of a corner.Math.sin(x)Math.tan(x)Parameter x is required.

JavaScript keywords and reserved words

You cannot use keywords, reserved words, true, false, and NULL as identifiers.The keywords in JS can be used to denote the start or end of a control statement, or to perform a specific operation. By rule, keywords are also language-reserved and

javascript-the distinction between null, undefined, and empty strings

I. separate judgment1 varA=NULL;2 //var a=undefined;3 //var a= ';4 //var a= ' DD ';5 if(!a&&typeofA = = ' object '){6Console.log (' A is null '))7}Else if(!a&&typeofA = = ' undefined '){8Console.log (' A is undefined ')9}Else if(!a&&typeofA = = '

JavaScript: Multi-line string

Original: http://www.cnblogs.com/ziyunfei/archive/2012/10/04/2711551.htmlThe function of a multiline string is to improve the readability of the source code. Especially when you are working with a predefined long string, dividing the string into

How to solve 0.1+0.2 in JavaScript is not equal to 0.3


  Console.log (0.1+0.2===0.3)// true or false??In normal mathematical logic, the logic of 0.1+0.2=0.3 is correct, but in JavaScript 0.1+0.2! ==0.3, what is this for? This question is also occasionally used as a face test to examine the

JavaScript represents the Y power of X


Example of an exponential operator (* *)console.log(2 ** 2); // 4console.log(3 ** 2); // 9console.log('3' ** '2'); // 9console.log((() => { let x = 2; let y = 3; x **= y; return x;})()); // 8II, Math.pow () 1. DefinitionThe Math.pow ()

Talking about JavaScript events (event handlers)

An event is an action that is performed by the user or by the browser itself. such as click, Load, and mouseover are the names of the events. The function that responds to an event is called an event handler. The name of the event handler begins

JavaScript Array method Daquan (recommended for Gray)

Array creationThere are two ways to create arrays in JavaScript, the first of which is to use the array constructor:? 123 vararr1 = new Array(); //创建一个空数组var arr2 = new Array(20); // 创建一个包含20项的数组var arr3 = newArray("lily","lucy",

JavaScript Object-Oriented Programming Guide reading notes ②

OverviewJavaScript Object-Oriented Programming Guide reading notes ①Here are just a few things I read about the JavaScript Object-oriented Programming guide. Those simple knowledge I did not record, I only record a few easy to omit or the wonderful

JavaScript Learning Notes: DOM node overview

0x01The DOM is the interface of the JavaScript Operation Web page, all called the Document Object model. Its role is to convert the Web page into a JavaScript object, so that you can use JavaScript to do various things (such as adding and deleting

JavaScript Learning Notes: DOM node relationships and operations

0x01: Previous WordsThe DOM can depict any HTML as a structure composed of multiple nodes. The nodes are divided into 12 different types, each representing different information and tags in the document. Each node has its own characteristics, data,

JavaScript Regular expression pattern matching (5)-Special character matching, newline mode

Special character Matching1 var pattern=/\[/; // use the \ symbol to escape special characters in the regular to match 2 var str= ' ['; 3 alert (pattern.test (str));Line break mode1 var pattern=/\d+/g; // Unqualified first match 2 var str= '

JavaScript Learning record day6-function variable scope, deconstruction assignment and method

JavaScript Learning record day6-function variable scope, deconstruction assignment and method@ (learning) [JavaScript][TOC]1. ScopeIn JavaScript, variables that are var declared are actually scoped.If a variable is declared inside the function body,

Carefully collected 48 JavaScript snippets, just 30 seconds to understand! (reproduced)

Anagrams of string (with duplicates)Use recursion. For each letter in a given string, create a crossword puzzle for the letter. Use map () to combine the letters with each part of the puzzle, and then use reduce () to combine all the crossword

Shorthand tips for JavaScript developers to know

This article comes from years of experience in JavaScript coding techniques that are suitable for all developers who are programming with JavaScript.The purpose of this article is to help you become more proficient in the use of JavaScript language

A detailed summary of JavaScript Date Object methods

Date Object method Method Description Date () Returns the date and time of day. GetDate () Returns the day of the one month (1 ~ 31) from the Date object. GetDay () Returns

Dom Document Object Model | Javascript

# After learning the object-oriented programming language such as Python, you can learn JavaScript in its way of thinking . # DOM Document Object model is equivalent to a package, or module, defines a number of classes, to do the operation of

JavaScript Strict mode

IntroducedECMAscript 5 added "strict mode", which will make JavaScript run under stricter conditions, the purpose of setting up "strict mode", mainly has the following several: Eliminate some unreasonable and unreasonable JavaScript grammar,

Object-oriented JavaScript

Object of JavaScriptAn object is a data type of JavaScript. An object can be considered an unordered collection of attributes, each of which is a key-value pair, and the property name is a string, so the object can be treated as a string-to-value

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