search
HomeWeb Front-endJS TutorialDetailed explanation of JavaScript numerical methods and properties

This article brings you relevant knowledge about javascript, which mainly introduces issues related to numerical methods and properties in JavaScript, including toSting, toFixed, toPrecision, etc., as follows Let's take a look, I hope it will be helpful to everyone.

Detailed explanation of JavaScript numerical methods and properties

[Related recommendations: javascript video tutorial, web front-end]

We know that in JavaScript, Not only do reference types have methods and properties, but the three basic data types of string, number, and boolean also have methods and properties.

Today we are going to compare the properties and properties of literal values ​​(strictly speaking, they should be Number objects). A summary of common methods is helpful for our systematic learning and mastering

Number object methods

All number methods can be used for any type of number (literal, variable or expression)

1. toSting() method

- Returns a numerical value as a string

Example:

var num = 100
var str = num.toString()  // 变量
var str1 = (99).toString()  // 字面量
var str2 = (100+99).toString()  // 表达式
console.log(str)  // '100'
console.log(str1)  // '99'
console.log(str2)  // '199'

2 . toFixed() method

- Returns a string value, which contains a number with the specified number of decimal places (will be rounded)

Parameters: Receives a number indicating precision

Example:  

var num = 9.656
var num1 = num.toFixed(0)
var num2 = num.toFixed(2)
var num3 = num.toFixed(4)
console.log(num1)  // 10
console.log(num2)  // 9.66
console.log(num3)  // 9.6560

3. toPrecision() method

- Returns a string value, which contains A number with a specified length

Parameter: Receive a number, indicating the total number of digits

Example:    

var num = 9.656
var num1 = num.toPrecision()  // 省略参数表示原数
var num2 = num.toPrecision(2)
var num3 = num.toPrecision(4)
console.log(num1)  // 9.656
console.log(num2)  // 9.7
console.log(num3)  // 9.656

4. toExponential( ) Method

- Returns a string value that contains a number that has been rounded and used exponential notation

Parameters: Receives a number, defining the number of characters after the decimal point

Example:       

var num = 9.656
var num1 = num.toExponential(2)  // 省略参数表示原数
var num2 = num.toExponential(4)
ar num3 = num.toExponential(6)
console.log(num1)  // 9.66e+0
console.log(num2)  // 9.6560e+0
console.log(num3)  // 9.656000e+0

5. valueOf() method

- Return the value as a numerical value

Example:   

var num = 100
var num1 = num.valueOf()  // 变量
var num2 = (99).valueOf()  // 字面量
var num3 = (100+99).valueOf()  // 表达式
console.log(num1)  // 100
console.log(num2)  // 99
console.log(num3)  // 199

Note: Basically, this method will not be used for values ​​​​in the code, because the valueOf() method is used internally in JavaScript to convert the Number object into a primitive value

TIPS: All JavaScript data types have valueOf() and toString() methods

Convert variables into numbers

These three JS methods can be used to convert variables into numbers

  • Number() method

  • parseInt() method

  • parseFloat() Methods

It should be noted that these methods are global methods, not methods of numerical objects

Number object properties (not commonly used)

  • MAX_VALUE Returns the maximum number possible in JS

  • MIN_VALUE Returns the minimum number possible in JS

  • NEGATIVE_INFINITY Indicates negative Infinity

  • ## NaN                                 ‖                                        ional in infinity_NaN                                                            ure                                                                                                           -  

    MAX_VALUE Returns the largest possible number in JavaScript
  • MIN_VALUE Returns the smallest possible number in JavaScript

    Example:
  • var x = Number.MAX_VALUE
    var y = Number.MIN_VALUE
    console.log(x)  // 1.7976931348623157e+308
    console.log(y)   // 5e-324
POSITIVE_INFINITY Represents positive infinity (overflow Return on time)

NEGATIVE_INFINITY Represents negative infinity (return on overflow)

Example:

var x = 1 / 0
var y = -1 / 0
console.log(x)  // Infinity
console.log(y)   // -Infinity

NaN Non-number

NaN is a reserved word in JavaScript and represents NaN is an illegal number (not a number)

Example:

var x = 100 / 'apple'
console.log(x)  // NaN

Numeric attributes cannot be used for variables

Numeric attributes belong to the JavaScript number object wrapper named number

In layman’s terms, these properties can only be accessed by Number.MAX_VALUE

Example:

var x = 6
var y = x.MAX_VALUE  // 变量访问
var z = Number.MAX_VALUE  // 数字对象访问
console.log(y)  // undefined
console.log(z)  // 1.7976931348623157e+308

[Related recommendations:

javascript video tutorial

,

web front end

The above is the detailed content of Detailed explanation of JavaScript numerical methods and properties. For more information, please follow other related articles on the PHP Chinese website!

Statement
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
From Websites to Apps: The Diverse Applications of JavaScriptFrom Websites to Apps: The Diverse Applications of JavaScriptApr 22, 2025 am 12:02 AM

JavaScript is widely used in websites, mobile applications, desktop applications and server-side programming. 1) In website development, JavaScript operates DOM together with HTML and CSS to achieve dynamic effects and supports frameworks such as jQuery and React. 2) Through ReactNative and Ionic, JavaScript is used to develop cross-platform mobile applications. 3) The Electron framework enables JavaScript to build desktop applications. 4) Node.js allows JavaScript to run on the server side and supports high concurrent requests.

Python vs. JavaScript: Use Cases and Applications ComparedPython vs. JavaScript: Use Cases and Applications ComparedApr 21, 2025 am 12:01 AM

Python is more suitable for data science and automation, while JavaScript is more suitable for front-end and full-stack development. 1. Python performs well in data science and machine learning, using libraries such as NumPy and Pandas for data processing and modeling. 2. Python is concise and efficient in automation and scripting. 3. JavaScript is indispensable in front-end development and is used to build dynamic web pages and single-page applications. 4. JavaScript plays a role in back-end development through Node.js and supports full-stack development.

The Role of C/C   in JavaScript Interpreters and CompilersThe Role of C/C in JavaScript Interpreters and CompilersApr 20, 2025 am 12:01 AM

C and C play a vital role in the JavaScript engine, mainly used to implement interpreters and JIT compilers. 1) C is used to parse JavaScript source code and generate an abstract syntax tree. 2) C is responsible for generating and executing bytecode. 3) C implements the JIT compiler, optimizes and compiles hot-spot code at runtime, and significantly improves the execution efficiency of JavaScript.

JavaScript in Action: Real-World Examples and ProjectsJavaScript in Action: Real-World Examples and ProjectsApr 19, 2025 am 12:13 AM

JavaScript's application in the real world includes front-end and back-end development. 1) Display front-end applications by building a TODO list application, involving DOM operations and event processing. 2) Build RESTfulAPI through Node.js and Express to demonstrate back-end applications.

JavaScript and the Web: Core Functionality and Use CasesJavaScript and the Web: Core Functionality and Use CasesApr 18, 2025 am 12:19 AM

The main uses of JavaScript in web development include client interaction, form verification and asynchronous communication. 1) Dynamic content update and user interaction through DOM operations; 2) Client verification is carried out before the user submits data to improve the user experience; 3) Refreshless communication with the server is achieved through AJAX technology.

Understanding the JavaScript Engine: Implementation DetailsUnderstanding the JavaScript Engine: Implementation DetailsApr 17, 2025 am 12:05 AM

Understanding how JavaScript engine works internally is important to developers because it helps write more efficient code and understand performance bottlenecks and optimization strategies. 1) The engine's workflow includes three stages: parsing, compiling and execution; 2) During the execution process, the engine will perform dynamic optimization, such as inline cache and hidden classes; 3) Best practices include avoiding global variables, optimizing loops, using const and lets, and avoiding excessive use of closures.

Python vs. JavaScript: The Learning Curve and Ease of UsePython vs. JavaScript: The Learning Curve and Ease of UseApr 16, 2025 am 12:12 AM

Python is more suitable for beginners, with a smooth learning curve and concise syntax; JavaScript is suitable for front-end development, with a steep learning curve and flexible syntax. 1. Python syntax is intuitive and suitable for data science and back-end development. 2. JavaScript is flexible and widely used in front-end and server-side programming.

Python vs. JavaScript: Community, Libraries, and ResourcesPython vs. JavaScript: Community, Libraries, and ResourcesApr 15, 2025 am 12:16 AM

Python and JavaScript have their own advantages and disadvantages in terms of community, libraries and resources. 1) The Python community is friendly and suitable for beginners, but the front-end development resources are not as rich as JavaScript. 2) Python is powerful in data science and machine learning libraries, while JavaScript is better in front-end development libraries and frameworks. 3) Both have rich learning resources, but Python is suitable for starting with official documents, while JavaScript is better with MDNWebDocs. The choice should be based on project needs and personal interests.

See all articles

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

Video Face Swap

Video Face Swap

Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Tools

Dreamweaver CS6

Dreamweaver CS6

Visual web development tools

SAP NetWeaver Server Adapter for Eclipse

SAP NetWeaver Server Adapter for Eclipse

Integrate Eclipse with SAP NetWeaver application server.

MantisBT

MantisBT

Mantis is an easy-to-deploy web-based defect tracking tool designed to aid in product defect tracking. It requires PHP, MySQL and a web server. Check out our demo and hosting services.

Zend Studio 13.0.1

Zend Studio 13.0.1

Powerful PHP integrated development environment

PhpStorm Mac version

PhpStorm Mac version

The latest (2018.2.1) professional PHP integrated development tool