How to use if conditional statement in JavaScript
if in How to use if conditional statement in How to use if conditional statement in How to use if conditional statement in JavaScript can implement conditional branches, which are conditional statements. Therefore, the following article will introduce to you the usage of if conditional statements in How to use if conditional statement in How to use if conditional statement in How to use if conditional statement in JavaScript. Let’s take a look at the specific content.
Let’s first take a look at the syntax of the conditional branch (if statement) statement
if（条件）{
条件为真时执行
}in ( ). If the condition is true, the processing in {} will be executed.
By the way, consistent conditions are called "true", and inconsistent conditions are called "false".
If you want to add "false" to the if statement, you need to add the code as follows
if（条件）{
条件为真时执行
} else {
条件为假时执行
}If the condition is applicable, use if processing, if not, use else processing.
Specific example
Use scores to judge
If it is 80 points or more (including 80 points), then congratulations! Passed!
If the score is less than 80, you are not qualified! Work harder next time!
First, let us assume that the score is obtained using variables as follows (set to 90 points here).
The code is as follows
<script>
var score = 90;
if (score >= 80) {
document.write("恭喜你！通过了！") ;
}
</script>Because the score is higher than 80 points, the running results are as follows
Let’s look at a piece of code again
<script>
var score = 90;
if (score >= 80) {
document.write("恭喜你！通过了！");
} else {
document.write("不合格！下次努力！");
}
</script>Although this code adds else, since the score is still higher than 80, the result is still "Congratulations! Passed!"
Let's compare the scores Set to 60
<script>
var score = 60;
if (score >= 80) {
document.write("恭喜你！通过了！");
} else {
document.write("不合格！下次努力！");
}
</scriptThe running results are as follows
Multiple conditional branch statements (else if)
When using conditional statements, you can use multiple conditions to branch. At this time, the else if statement is used.
The else if statement in the conditional statement is as follows
<script>
if (条件) {
条件为真时执行
} else if (条件2) {
条件2为真时执行
}
else {
条件为假时执行
}
</script>Let’s look at a specific example
<script>
var score = 60;
if (score >= 80) {
document.write("恭喜你！通过了！");
} else if (score >= 70) {
document.write("不合格！加油！");
}
else {
document.write("不合格！下次努力！");
}
</script>The running results are as follows
The above is the detailed content of How to use if conditional statement in JavaScript. For more information, please follow other related articles on the PHP Chinese website!
Hot AI Tools
Undresser.AI Undress
AI-powered app for creating realistic nude photos
AI Clothes Remover
Online AI tool for removing clothes from photos.
Undress AI Tool
Undress images for free
Clothoff.io
AI clothes remover
Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!
Hot Article
Hot Tools
Notepad++7.3.1
Easy-to-use and free code editor
SublimeText3 Chinese version
Chinese version, very easy to use
Zend Studio 13.0.1
Powerful PHP integrated development environment
Dreamweaver CS6
Visual web development tools
SublimeText3 Mac version
God-level code editing software (SublimeText3)
Hot Topics
What should I do if I encounter garbled code printing for front-end thermal paper receipts?
Apr 04, 2025 pm 02:42 PM
Frequently Asked Questions and Solutions for Front-end Thermal Paper Ticket Printing In Front-end Development, Ticket Printing is a common requirement. However, many developers are implementing...
Demystifying JavaScript: What It Does and Why It Matters
Apr 09, 2025 am 12:07 AM
JavaScript is the cornerstone of modern web development, and its main functions include event-driven programming, dynamic content generation and asynchronous programming. 1) Event-driven programming allows web pages to change dynamically according to user operations. 2) Dynamic content generation allows page content to be adjusted according to conditions. 3) Asynchronous programming ensures that the user interface is not blocked. JavaScript is widely used in web interaction, single-page application and server-side development, greatly improving the flexibility of user experience and cross-platform development.
Who gets paid more Python or JavaScript?
Apr 04, 2025 am 12:09 AM
There is no absolute salary for Python and JavaScript developers, depending on skills and industry needs. 1. Python may be paid more in data science and machine learning. 2. JavaScript has great demand in front-end and full-stack development, and its salary is also considerable. 3. Influencing factors include experience, geographical location, company size and specific skills.
How to merge array elements with the same ID into one object using JavaScript?
Apr 04, 2025 pm 05:09 PM
How to merge array elements with the same ID into one object in JavaScript? When processing data, we often encounter the need to have the same ID...
Is JavaScript hard to learn?
Apr 03, 2025 am 12:20 AM
Learning JavaScript is not difficult, but it is challenging. 1) Understand basic concepts such as variables, data types, functions, etc. 2) Master asynchronous programming and implement it through event loops. 3) Use DOM operations and Promise to handle asynchronous requests. 4) Avoid common mistakes and use debugging techniques. 5) Optimize performance and follow best practices.
How to achieve parallax scrolling and element animation effects, like Shiseido's official website?
or:
How can we achieve the animation effect accompanied by page scrolling like Shiseido's official website?
Apr 04, 2025 pm 05:36 PM
Discussion on the realization of parallax scrolling and element animation effects in this article will explore how to achieve similar to Shiseido official website (https://www.shiseido.co.jp/sb/wonderland/)...
The Evolution of JavaScript: Current Trends and Future Prospects
Apr 10, 2025 am 09:33 AM
The latest trends in JavaScript include the rise of TypeScript, the popularity of modern frameworks and libraries, and the application of WebAssembly. Future prospects cover more powerful type systems, the development of server-side JavaScript, the expansion of artificial intelligence and machine learning, and the potential of IoT and edge computing.
The difference in console.log output result: Why are the two calls different?
Apr 04, 2025 pm 05:12 PM
In-depth discussion of the root causes of the difference in console.log output. This article will analyze the differences in the output results of console.log function in a piece of code and explain the reasons behind it. �...
