How to use for loop in js

The for loop in JavaScript is a loop structure used to repeatedly execute a block of code. It works through three phases: initialization, conditions, and increment, which are executed at the beginning of the loop, before it starts, and after it completes.

Using for loop in JavaScript

The for loop is a method in JavaScript that is used to repeatedly execute a specific block of code. Loop structure. The syntax is as follows:

for (initialization; condition; increment) { // 循环体：要重复执行的代码 }

Working principle:

1. Initialization (initialization):Executed once at the beginning of the loop. Usually used to declare variables or set initial values.
2. condition (condition):Condition checked before each loop starts. If the condition is true, execute the loop body; otherwise, exit the loop.
3. increment:Executed after each loop is completed. Typically used to increment or update loop variables.

Example:

// 循环 5 次 for (let i = 0; i < 5; i++) { console.log(`循环第 ${i + 1} 次`); } // 循环数组 const arr = [1, 2, 3, 4, 5]; for (let j = 0; j < arr.length; j++) { console.log(arr[j]); }

Other notes:

• Initialization and increment statements can be omitted, But conditional statements are required.
• The loop body can contain any JavaScript code.
• You can use thebreakstatement to exit the loop early.
• You can use thecontinuestatement to skip the current loop and continue executing the next loop.

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