JavaScript Fundamentals for Grade 9

What is a variable in JavaScript?

• A variable in JavaScript is a type of loop used for iteration.

• A variable in JavaScript is a function that performs calculations.

• A variable in JavaScript is a method for defining classes.

• A variable in JavaScript is a named container for storing data values.

Which of the following is a valid way to declare a variable?

• let x = 5;

• x := 5;

• const x = 5;

• var x = 5;

What data type is used to represent true or false values?

• integer

• boolean

• string

• float

How do you create a random number between 1 and 10 in JavaScript?

• Math.ceil(Math.random() * 10)

• Math.floor(Math.random() * 10) + 1

• Math.random() * 10

• Math.floor(Math.random() * 11)

What is the result of the expression '5' + 5 in JavaScript?

• 55

• 55.0

• '55'

• 10

What keyword is used to declare a constant variable?

• const

• final

• static

• immutable

How do you write a conditional statement in JavaScript?

• if (condition) { // code to execute if condition is true } else { // code to execute if condition is false }

• if condition { // code }

• condition ? // code : // code to execute

• if (condition) // code to execute

What is the purpose of the 'if' statement?

• To declare a function in the code.

• To create a loop for repeated execution.

• To define a variable in a program.

• To control the flow of execution based on conditions.

How can you listen for a click event on a button in JavaScript?

• $('button').click(function() { /* your code here */ });

• document.querySelector('button').addEventListener('click', function() { /* your code here */ });

• document.getElementById('button').onClick = function() { /* your code here */ };

• button.addEventListener('touchstart', function() { /* your code here */ });

What is the output of the following code: console.log(typeof 'Hello')?

• string

• boolean

• number

• undefined