Home Web Front-end JS Tutorial Basic JavaScript knowledge summary (3) comparison operators and logical operators

Basic JavaScript knowledge summary (3) comparison operators and logical operators

Mar 10, 2018 am 11:50 AM
javascript js Compare

This time I will bring you a basic knowledge summary of JavaScript. There are a total of eleven knowledge points. Basic JavaScript knowledge summary (3)Comparison operators, Logical operator, the following is a practical case, let’s take a look.

Write at the front

js (2) mentioned simple addition, subtraction, multiplication and division. Now let’s talk about the other two operators

Comparison operators

“>”、“<”、“==”、“>=”、“<=”、“!=”
Copy after login

The result of the comparison is a boolean value

Logical operator

“&&”、“||”、“!”
Copy after login

The result of the operation is the real value

The value that is considered false

undefined、null、NaN、""、0、false
Copy after login

Calculation Operator

var a = 10,
    b = 20,
    c;
    c = a < b;//true
    c = a > b;//false
    c = "a" > "b"//false,比较的ascll码值
    c = a == b// false
    c = a != b//false
    c = NaN == NaN//false,NaN不等于任何数;
Copy after login

Logical operator

//Logical AND &&var a = 1 && 2//Print out a-->2//Logical OR||var a = 1 || 3;//Print out a-->1//Logical not! Convert to Boolean value and invert var a = !123;//false;

Logical AND&& Let’s look at the first one first The result of converting an expression to a Boolean value. If it is true, then it will look at the result of converting the second expression to a Boolean value. Then if there are only two expressions, it will only look at the second one. Expression, you can return the value of the expression, a short-circuit statement;

I believe you have mastered the method after reading the case in this article. For more exciting information, please pay attention to other related articles on the PHP Chinese website!

Related reading:

Summary of basic JavaScript knowledge (2) Introduction, variables, value types, operators

Summary of basic JavaScript knowledge (1)

The above is the detailed content of Basic JavaScript knowledge summary (3) comparison operators and logical operators. For more information, please follow other related articles on the PHP Chinese website!

Statement of this Website
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

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

Notepad++7.3.1

Notepad++7.3.1

Easy-to-use and free code editor

SublimeText3 Chinese version

SublimeText3 Chinese version

Chinese version, very easy to use

Zend Studio 13.0.1

Zend Studio 13.0.1

Powerful PHP integrated development environment

Dreamweaver CS6

Dreamweaver CS6

Visual web development tools

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)

Hot Topics

Java Tutorial
1655
14
PHP Tutorial
1252
29
C# Tutorial
1226
24
How to enable nfc function on Xiaomi Mi 14 Pro? How to enable nfc function on Xiaomi Mi 14 Pro? Mar 19, 2024 pm 02:28 PM

Nowadays, the performance and functions of mobile phones are becoming more and more powerful. Almost all mobile phones are equipped with convenient NFC functions to facilitate users for mobile payment and identity authentication. However, some Xiaomi 14Pro users may not know how to enable the NFC function. Next, let me introduce it to you in detail. How to enable nfc function on Xiaomi 14Pro? Step 1: Open the settings menu of your phone. Step 2: Find and click the &quot;Connect and Share&quot; or &quot;Wireless &amp; Networks&quot; option. Step 3: In the Connection &amp; Sharing or Wireless &amp; Networks menu, find and click &quot;NFC &amp; Payments&quot;. Step 4: Find and click &quot;NFC Switch&quot;. Normally, the default is off. Step 5: On the NFC switch page, click the switch button to switch it to on.

Recommended: Excellent JS open source face detection and recognition project Recommended: Excellent JS open source face detection and recognition project Apr 03, 2024 am 11:55 AM

Face detection and recognition technology is already a relatively mature and widely used technology. Currently, the most widely used Internet application language is JS. Implementing face detection and recognition on the Web front-end has advantages and disadvantages compared to back-end face recognition. Advantages include reducing network interaction and real-time recognition, which greatly shortens user waiting time and improves user experience; disadvantages include: being limited by model size, the accuracy is also limited. How to use js to implement face detection on the web? In order to implement face recognition on the Web, you need to be familiar with related programming languages ​​and technologies, such as JavaScript, HTML, CSS, WebRTC, etc. At the same time, you also need to master relevant computer vision and artificial intelligence technologies. It is worth noting that due to the design of the Web side

iPhone 16 Pro CAD drawings exposed, adding a second new button iPhone 16 Pro CAD drawings exposed, adding a second new button Mar 09, 2024 pm 09:07 PM

The CAD files of the iPhone 16 Pro have been exposed, and the design is consistent with previous rumors. Last fall, the iPhone 15 Pro added an Action button, and this fall, Apple appears to be planning to make minor adjustments to the size of the hardware. Adding a Capture button According to rumors, the iPhone 16 Pro may add a second new button, which will be the second consecutive year to add a new button after last year. It is rumored that the new Capture button will be set on the lower right side of the iPhone 16 Pro. This design is expected to make camera control more convenient and also allow the Action button to be used for other functions. This button will no longer be just an ordinary shutter button. Regarding the camera, from the current iP

How to use TikTok on Huawei Pocket2 remotely? How to use TikTok on Huawei Pocket2 remotely? Mar 18, 2024 pm 03:00 PM

Sliding the screen through the air is a feature of Huawei that is highly praised in the Huawei mate60 series. This feature uses the laser sensor on the phone and the 3D depth camera of the front camera to complete a series of functions that do not require The function of touching the screen is, for example, to use TikTok from a distance. But how should Huawei Pocket 2 use TikTok from a distance? How to take screenshots from the air with Huawei Pocket2? 1. Open the settings of Huawei Pocket2 2. Then select [Accessibility]. 3. Click to open [Smart Perception]. 4. Just turn on the [Air Swipe Screen], [Air Screenshot], and [Air Press] switches. 5. When using it, you need to stand 20~40CM away from the screen, open your palm, and wait until the palm icon appears on the screen.

How to set line spacing in WPS Word to make the document neater How to set line spacing in WPS Word to make the document neater Mar 20, 2024 pm 04:30 PM

WPS is our commonly used office software. When editing long articles, the fonts are often too small to be seen clearly, so the fonts and the entire document are adjusted. For example: adjusting the line spacing of the document will make the entire document very clear. I suggest that all friends learn this operation step. I will share it with you today. The specific operation steps are as follows, come and take a look! Open the WPS text file you want to adjust, find the paragraph setting toolbar in the [Start] menu, and you will see the small line spacing setting icon (shown as a red circle in the picture). 2. Click the small inverted triangle in the lower right corner of the line spacing setting, and the corresponding line spacing value will appear. You can choose 1 to 3 times the line spacing (as shown by the arrow in the figure). 3. Or right-click the paragraph and it will appear.

TrendX Research Institute: Merlin Chain project analysis and ecological inventory TrendX Research Institute: Merlin Chain project analysis and ecological inventory Mar 24, 2024 am 09:01 AM

According to statistics on March 2, the total TVL of Bitcoin’s second-layer network MerlinChain has reached US$3 billion. Among them, Bitcoin ecological assets accounted for 90.83%, including BTC worth US$1.596 billion and BRC-20 assets worth US$404 million. Last month, MerlinChain’s total TVL reached US$1.97 billion within 14 days of launching staking activities, surpassing Blast, which was launched in November last year and is also the most recent and equally eye-catching. On February 26, the total value of NFTs in the MerlinChain ecosystem exceeded US$420 million, becoming the public chain project with the highest NFT market value besides Ethereum. Project Introduction MerlinChain is an OKX support

The difference and comparative analysis between C language and PHP The difference and comparative analysis between C language and PHP Mar 20, 2024 am 08:54 AM

Differences and comparative analysis between C language and PHP C language and PHP are both common programming languages, but they have obvious differences in many aspects. This article will conduct a comparative analysis of C language and PHP and illustrate the differences between them through specific code examples. 1. Syntax and usage: C language: C language is a process-oriented programming language, mainly used for system-level programming and embedded development. The syntax of C language is relatively simple and low-level, can directly operate memory, and is efficient and flexible. C language emphasizes the programmer's completeness of the program

How to use Xiaomi Mi 14 Ultra AI smart image expansion? How to use Xiaomi Mi 14 Ultra AI smart image expansion? Mar 16, 2024 pm 12:37 PM

The progress of the times has made many people's incomes higher and higher, and the mobile phones they usually use will be changed frequently. The Xiaomi Mi 14 Ultra recently launched by Xiaomi must be familiar to users. It has very high performance configuration and can provide users with more In order to provide a comfortable and smooth experience, new mobile phones will inevitably encounter many functions that are not used. For example, how to use Xiaomi 14UltraAI smart image expansion? Come and take a look at the usage tutorial below! How to use Xiaomi 14UltraAI smart image expansion? First open Xiaomi 14Ultra, enter the photo album, select the picture you want to enlarge, and enter the photo album editing option. Click Crop Rotate, click Crop, and click Smart Expand in the selection that appears. Finally, choose the way to expand the image according to your own needs.

See all articles