Loops in JavaScript

The usage of loops to repeat group of instructions many time. Sometimes when you write code, you want the run same block of code a number of times. You can use looping statements in your code..

There are three types of conditional statements:
1) For Loop
2) while loop
3) do..while loop

For Loop

For loops are used to do something a set number of times.
The first parameter of "for" is executed the first time and it is used to initiate the variable of the loop, the second parameter indicates the condition to be achieved so that the loop will continue executing, and third parameter is a statement that executes at the end of every iteration and updates the value of the iteration variable.

Syntax

Example

In this example, the looop will run 10 times because you have started initialization from 1($i=1) and conditionis less than or equal to 10 ($i<=10) and this will increment of 1 ($i++):

While Loop

While loops are pieces of code which will repeat until the condition is met.

Syntax:

At the end of each block execution, the while condition is tested again. If the condition holds a true value, the code block will be executed again. Otherwise if the condition holds a false value, the code block will complete its operation.

Example:

The above example demonstrates a loop that will continue to run as long as the variable i is less than, or equal to 10. i will increase by 1 each time the loop runs:

Output

Do.. while loop

Do..while loops are pieces of code which will repeat until the condition is true. It is opposite of while loop

Example

The above example will increment the value of test at least once, and it will continue incrementing the variable test while it has a value of less than 10: