What is the correct way to declare a variable in JavaScript?
A). var x = 10;
B). let x = 10;
C). const x = 10;
D). variable x = 10;
How can you convert a string to a number in JavaScript?
A). parseInt('10')
B). parseFloat('10.5')
C). Number('10')
D). All of the above
What does the '===' operator check in JavaScript?
A). Type and value equality
B). Type equality only
C). Value equality only
D). Reference equality
What is the purpose of the 'typeof' operator in JavaScript?
A). To check if a variable is defined
B). To check the data type of a variable
C). To assign a data type to a variable
D). To increment the value of a variable
What is the purpose of the 'constructor' method in a JavaScript class?
A). To create new instances of the class
B). To initialize class properties
C). To define class methods
D). To define class inheritance
Which statement correctly declares a JavaScript function?
A). function greet() {}
B). const greet = function() {}
C). const greet = () => {}
D). const greet = {}
How do you concatenate strings in JavaScript?
A). Using the + operator
B). Using the - operator
C). Using the * operator
D). Using the / operator
Which statement correctly declares a JavaScript array?
A). let colors = ['red', 'green'];
B). const colors = {'red', 'green'};
C). const colors = ['red', 'green'];
D). var colors = ('red', 'green');
What is the purpose of the 'this' keyword in JavaScript?
A). To refer to the current HTML element
B). To refer to the current JavaScript file
C). To refer to the current object
D). To refer to the current function
Which statement correctly declares a JavaScript object?
A). let person = {name: 'John', age: 30};
B). const person = ('name' => 'John', 'age' => 30);
C). const person = ['name', 'John', 'age', 30];
D). var person = {name: 'John', age: 30};