The for loop is one of the most commonly used loops in JavaScript. It is perfect when you know in advance how many times a block of code should run.
A for loop has three parts:
- Initialization – where the loop starts
- Condition – when the loop should stop
- Update – how the loop changes each time
Understanding these three parts helps you control repetition easily.
When to Use the for Loop
- When repeating code a fixed number of times
- When counting numbers
- When looping through lists or arrays
- When generating tables or patterns
- When processing data step by step
The for loop gives you full control over how many times code runs.
In this example, the loop starts with i = 1 and runs as long as i is less than or equal to 5.
After each run, the value of i increases by 1. This shows how the loop controls repetition.
Here, the loop counts backwards from 5 to 1. The update part uses i-- to decrease the value of i.
This is useful in timers, countdowns, and reverse processing.
This example shows how a for loop can perform calculations while repeating code.
By mastering the for loop, students can handle repetition, perform data processing, and build strong logic for real-world applications.