Course Content
Introduction to JavaScript
Introduction to JavaScript
Understanding the while Loop in JavaScript
Loop Types
Loops are structures that repeatedly execute a code block while a specific condition is true. In JavaScript, there are three types of loops:
while;
do-while;
for.
Let's explore each of them in detail.
while Loop
The while
loop is the simplest type of loop. It continues to execute a code block as long as the specified condition remains true.
To create a while
loop, use the while
keyword followed by a condition in parentheses and enclose the code block in curly braces. The syntax is similar to that of an if
statement:
javascript
Here's an example:
let a = 5; while (a <= 10) { console.log("a =", a); a++; }
In this example, the while
loop's code block executes six times:
Initially, the variable
a
is set to5
;The loop condition is
a <= 10
, which is true, so the code block is executed;After each execution, the variable
a
is incremented by 1;The loop continues to execute as long as the condition remains true.
Note
The
while
loop checks the condition before executing the code block. If the condition is initiallyfalse
, the code block will not be executed.
Note
Be cautious with the condition! If the condition always evaluates to
true
, the loop will never break, resulting in an infinite loop, which can cause your program to hang or become unresponsive.
1. How many times will the program print Hello!
?
2. How many times will the program print JavaScript
?
3. How many times will the program print Be careful!
?
Thanks for your feedback!