Technology & IT Skills
JavaScript control structures quiz: Test your flow and logic skills
This 20-question quiz helps you practice JavaScript control structures-if/else, switch, and loops-so you can spot logic errors fast. Get instant feedback, short explanations, and pointers to review topics like truthy/falsy and break/continue. For more practice, try the programming basics quiz, build DOM skills with the jQuery quiz, or challenge yourself with a Java programming quiz.
Take the Quiz
1Which of the following is the correct syntax for an if statement in JavaScript?
2Which operator is used to compare both value and type in JavaScript?
3Which keyword is used to exit a case in a switch statement?
4Which loop guarantees that the code block executes at least once in JavaScript?
5What does the 'continue' statement do in a loop in JavaScript?
6Given a variable x with value 5, which if statement correctly checks if x is greater than 3 and less than 10?
7In a for loop, which part is used to update the loop variable after each iteration?
8What is the output of the following code snippet?
let count = 0;
while (count < 3) {
console.log(count);
count++;
}
9Which of the following statements about the ternary operator in JavaScript is correct?
10What will be logged if the following code is executed?
for (let i = 0; i < 3; i++) {
if (i === 1) continue;
console.log(i);
}
11In a switch statement, what happens when no matching case is found and a default block is provided?
12Which logical operator in JavaScript returns true if at least one operand is truthy?
13In JavaScript, what is the purpose of the break statement inside a loop?
14Which of the following is a valid use of the do...while loop?
15How can you check if a variable, myVar, is defined and not null in JavaScript?
16Consider the following code snippet:
let x = 0;
while (x < 10) {
if (x % 2 === 0) {
x += 3;
} else {
x++;
}
console.log(x);
}
Which of the following best describes the iteration behavior in this loop?
17What is the result of the following logical expression: !((false || true) && !(false && true))?
18In a switch-case structure, what problem might arise from not using break statements?
19In a nested loop scenario, which statement can be used to exit only the inner loop without affecting the outer loop?
20How does short-circuit evaluation in logical operators enhance performance in control flow statements in JavaScript?
Learning Goals
Study Outcomes
- Understand how to implement conditional statements in JavaScript.
- Apply looping constructs to manage iterative processes.
- Analyze code to identify and resolve logical flow issues.
- Evaluate and debug control structure implementations.
- Interpret coding puzzles to enhance logical reasoning skills.
Study Guide
4.12.1 JavaScript Control Structures Cheat Sheet
- Master the if Statement - The
ifstatement is your basic decision-maker. It checks a condition and runs the code inside its block only when that condition is true, giving you control over what happens next. Practice simple age or score checks to see how it branches your program flow! Read more on GeeksforGeeks - Utilize if...else for Decision Making - The
if...elsestructure lets you choose between two paths: one when the condition is true, and another when it's false. It's perfect for scenarios like pass/fail messages or feature toggles. Embrace both sides of the coin to keep your logic clear and concise! Read more on GeeksforGeeks - Implement if...else if...else for Multiple Conditions - When two options aren't enough, chain together
else ifblocks to handle extra cases. This lets you cover several scenarios in a neat, ordered sequence - ideal for grading systems or temperature ranges. Just watch out for overlapping conditions to avoid surprises! Read more on GeeksforGeeks - Understand the switch Statement - The
switchstatement compares a single expression against many cases, making it cleaner than a long chain ofif...else if. It's like a multiple-choice quiz: pick the matching case and run its block. Don't forgetbreakafter each case to prevent fall‑through! Read more on GeeksforGeeks - Practice the for Loop - The
forloop is your go-to when you know in advance how many times you want to run a block of code. It bundles initialization, condition-checking, and iteration in one line - perfect for counting or iterating over arrays. Master it to automate repetitive tasks effortlessly! Read more on GeeksforGeeks - Explore the while Loop - The
whileloop repeats its block as long as the condition stays true, giving you flexibility when you don't know the iteration count up front. Just be mindful to update your condition inside the loop to avoid infinite loops that crash your code! Read more on GeeksforGeeks - Learn the do...while Loop - The
do...whileloop guarantees at least one run of its block before checking the condition, making it ideal for user prompts or menu displays. Use it when you want an initial action followed by a repeat check - no extra flags needed! Read more on GeeksforGeeks - Use the break Statement -
breakis your emergency stop inside loops orswitchstatements. It immediately exits the nearest loop or switch block, which is super handy when you've found what you're looking for or need to bail out early. Use it sparingly for cleaner logic! Read more on GeeksforGeeks - Apply the continue Statement -
continueskips the rest of the current loop iteration and jumps straight to the next one. It's like saying "not this time" when you hit a certain condition, letting you filter out unwanted cases without breaking the loop entirely. Perfect for data validation or selective processing! Read more on GeeksforGeeks - Understand the return Statement - Inside a function,
returnstops execution immediately and optionally sends a value back to the caller. It's how you package up results and exit gracefully - think of it as the function's way of handing back its final answer. Use it to keep your functions focused and efficient! Read more on GeeksforGeeks
Explore More
Technology Quizzes
AI-DraftedHuman-Reviewed
Reviewed by
Updated Feb 24, 2026