JavaScript Looping

Looping

Very often when you write code, you want the same block of code to run a number of times. You can use looping statements in your code to do this.

In JavaScript we have the following looping statements:

• while - loops through a block of code while a condition is true
• do...while - loops through a block of code once, and then repeats the loop while a condition is true
• for - run statements a specified number of times

while

The while statement will execute a block of code while a condition is true.. 

while (condition)
{
    code to be executed
}

do...while

The do...while statement will execute a block of code once, and then it will repeat the loop while a condition is true

do
{
    code to be executed
}
while (condition)

for

The for statement will execute a block of code a specified number of times

for (initialization; condition; increment)
{
    code to be executed
}

Examples

For loop
How to write a For loop. Use a For loop to run the same block of code a specified number of times

Looping through HTML headers
How to use the For loop to write the HTML headers.

While loop
How to write a While loop. Use a While loop to run the same block of code while or until a condition is true

Do while loop
How to write a Do While loop. Use a Do While loop to run the same block of code while or until a condition is true. This loop will always be executed once, even if the condition is false, because the statements are executed before the condition is tested