If–else statement in Javascript - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of an if–else statement in JavaScript?

An if–else statement lets the program choose between two paths: one if a condition is true, and another if it is false.

beginner

Write the basic syntax of an if–else statement in JavaScript.

if (condition) {<br> // code runs if condition is true<br>} else {<br> // code runs if condition is false<br>}

beginner

What happens if the condition in an if statement is false and there is no else block?

The code inside the if block is skipped, and the program continues after the if statement without running any alternative code.

intermediate

Can you use multiple else if blocks in JavaScript? What is their purpose?

Yes, multiple else if blocks let you check several conditions in order, running the code for the first true condition.

beginner

Explain with an example how if–else helps in decision making in code.

Example:<br>if (temperature > 30) {<br> console.log('It is hot');<br>} else {<br> console.log('It is not hot');<br>}<br>This helps the program decide what message to show based on temperature.

What will the following code print?<br>if (5 > 10) { console.log('Yes'); } else { console.log('No'); }

A Yes

B Nothing

C No

D Error

Since 5 is not greater than 10, the else block runs and prints 'No'.

Which keyword is used to check an additional condition after an if statement?

A else if

B else

C elseif

D elif

JavaScript uses 'else if' (two words) to check another condition after if.

What happens if the condition in an if statement is true?

A Nothing happens

B The else block runs

C The program stops

D The code inside the if block runs

When the condition is true, the code inside the if block runs.

Can an if statement exist without an else block?

A No, else is required

B Yes, else is optional

C Only if the condition is true

D Only if the condition is false

The else block is optional; you can have just an if statement.

What is the output of this code?<br>if (false) { console.log('A'); } else if (true) { console.log('B'); } else { console.log('C'); }

A B

B No output

C C

D A

The first condition is false, the else if condition is true, so it prints 'B'.

Describe how an if–else statement controls the flow of a program.

Think about how the program chooses what code to run based on a question.

Write a simple if–else statement in JavaScript that checks if a number is positive or not.

Use console.log to show messages for both cases.