Course Content
Introduction to JavaScript
Now let's take a look at loops.
A loop is a structure that executes a set of instructions repeatedly while a certain condition is true.
There are three types of loops in JavaScript:
- while;
- do-while;
- for.
Let's take a closer look at each one.
while
The while
is the most simple loop. This operator repeats the code block while the condition is true
.
To create this loop, you need to use the while
keyword with condition in parentheses (()
) and code block in curly brackets ({}
). This syntax is similar to the if
syntax:
Look at the example:
The interpreter checks the condition and executes the code block if the condition is true
. These actions repeat until the condition is false
:

Note
Be careful with the condition! If the condition always evaluates to true, the loop will never break and will run indefinitely. Such moments are called infinity loops.
How many times will the program output "Hello!"?
Select the correct answer
How many times will the program output "JavaScript"?
Select the correct answer
How many times will the program output "Be careful!"
Select the correct answer
Section 5.
Chapter 1