Notice: This page requires JavaScript to function properly.
Please enable JavaScript in your browser settings or update your browser.Learn Using the do while Loop for Iteration | Looping Through Data in JavaScript
Introduction to JavaScript
course content

Course Content

Introduction to JavaScript

Introduction to JavaScript

1. JavaScript Fundamentals
About JavaScriptUnderstanding JavaScript SyntaxChallenge: Console Output in JavaScriptUsing Comments to Document CodeChallenge: Write a Single-Line CommentChallenge: Write a Multi-Line Comment
2. Variables and Data Types in JavaScript
Understanding Variables in JavaScriptChallenge: Define the VariableUsing const for ConstantsExploring JavaScript Data TypesWorking with null in JavaScriptIntroduction to ArraysArray Methods and ManipulationChallenge: Perform Array Operations
3. Performing Operations in JavaScript
Understanding Assignment OperatorsMathematical Operations in JavaScriptAssignment Operators in JavaScriptIncrement and Decrement OperatorsChallenge: Variable Operations PracticeComparison Operators in JavaScriptLogical Operators ExplainedChallenge: Compare Variables in JavaScriptConcatenating Strings in JavaScriptChallenge: Build Sentences with JavaScript
4. Controlling Program Flow with Conditional Statements
Mastering if Statements in JavaScriptUsing else for Alternative OutcomesApplying else if for Multiple ConditionsChallenge: Determine Sizes with Conditionals
5. Looping Through Data in JavaScript
Understanding the while Loop in JavaScriptUsing the do while Loop for IterationChallenge: Print Numbers from 5 to 9Mastering the for Loop in JavaScriptChallenge: Console Tigers with LoopsBreaking Out of Loops with breakSkipping Iterations with continueChallenge: Stop and Skip in Loops
6. Functions in JavaScript
What Are Functions in JavaScript?Defining Functions in JavaScriptChallenge: Write a Function – My NameUsing Function Arguments EffectivelyReturning Values from FunctionsChallenge: Create a Sum FunctionCourse Summary & Next Steps

book
Using the do while Loop for Iteration

Let's consider the do-while loop. This loop is similar to the while loop but has a key distinction.

whiledo-while
Executes code block after the condition check.Executes code block before the condition check.

Syntax

The do-while loop begins with the do keyword, encloses the code block within curly braces {}, and concludes with the while keyword followed by the condition in parentheses () without the need for an additional code block:

js

Here's an example:


              
123456

            
let a = 0;

do {
  console.log(a);
  a++;
} while (a <= 3 && a >= 1);
copy

At the outset, the variable a was initialized to 0, and the condition a >= 1 was evaluated after the a++ operation.

The code block within the do is guaranteed to be executed at least once:


              
123456789

            
// `while` loop
while (false) {
  console.log("while"); // Not executed
}

// `do-while` loop
do {
  console.log("do-while"); // Executed 1 time
} while (false);
copy

The do-while loop is particularly useful when you need to prompt the user for input at least once and continue until the user enters valid data or meets a specific condition.

question mark

How many times will the following code print "Invalid PIN" to the console?

Select the correct answer

Everything was clear?

How can we improve it?

Thanks for your feedback!

SectionΒ 5. ChapterΒ 2
We're sorry to hear that something went wrong. What happened?
some-alt