- ✕この概要は、複数のオンライン ソースに基づいて AI を使用して生成されました。元のソース情報を表示するには、[詳細情報] リンクを使用します。
The else if statement in JavaScript is used to specify a new condition to test if the first condition is false. This allows for multiple conditions to be checked sequentially.
Example
let time = new Date().getHours();if (time < 10) {greeting = "Good morning";} else if (time < 20) {greeting = "Good day";} else {greeting = "Good evening";}console.log(greeting); // Output will depend on the current timeコピーしました。✕コピーIn this example, the code checks the current hour and assigns a different greeting based on the time of day.
Important Considerations
Nesting Else If Statements
Multiple else if statements can be nested to create complex conditional logic. However, it's important to use block statements {} to group multiple statements within each clause to avoid confusing behavior.
Truthy and Falsy Values
In JavaScript, any value that is not false, undefined, null, 0, NaN, or an empty string ("") is considered truthy. This means that even objects and arrays are considered truthy.
Best Practices
JavaScript if/else Statement - W3Schools
JavaScript - Conditional Statements - GeeksforGeeks
2 日前 · The if-else statement executes one block of code if a condition is true and another block if it is false. It ensures that exactly one of the two code blocks runs.
if...else - JavaScript - MDN
ブロック文およびさらにネストされた if 文を含む、どんな文であってもかまいません。 解説 複数の if...else 文をネストすることで、 else if 節を作成することができます。 JavaScript では（1 単語の） …
JavaScript if...else Statement (with Examples) - Programiz
The JavaScript if…else statement is used to execute/skip a block of code based on a condition. In this tutorial, we will learn about the JavaScript if…else statement …
JavaScript if...else Statement
2024年11月15日 · This tutorial introduces you to JavaScript if...else statement that executes a block if a condition is true or another block otherwise.
- 他の人も質問しています
How to Write JavaScript if else Statements with Examples
From basic if statement examples to complex nested conditional statements, this guide covers everything you need to write clean, efficient, and maintainable code.
JavaScript If/Else - Conditional Logic Explained - ZetCode
2025年4月16日 · Understand how to use if/else statements in JavaScript for controlling program flow, with examples and explanations.
Conditional branching: if, - The Modern JavaScript Tutorial
We recommend wrapping your code block with curly braces {} every time you use an if statement, even if there is only one statement to execute. Doing so …
JavaScript if, else and else if - GeeksforGeeks
2025年4月15日 · The else statement follows an if statement and provides an alternative block of code to run when the condition in the if statement is false. It is used for creating conditional logic that …
JavaScript if-else, else-if Explained with Real Examples
2025年6月23日 · JavaScript if-else, else-if Explained with Real Examples Learn JavaScript if, else, and else if conditional statements with syntax, use cases, and …
How to Write an If Else Statement in JavaScript について掘り下げる
コンテンツに移動
