What happens if you declare a variable without initializing it in JavaScript?
A). It will throw a syntax error
B). It will assign the variable a value of undefined
C). It will automatically assign a value to the variable
D). It will assign the variable a value of null
What will be the value of x after the following code executes: let x = '5' + 5;?
A). '55'
B). 10
C). 5
D). '10'
What will be the value of x after the following code executes: let x = 10; x += 5;?
A). 15
B). 5
C). 10
D). undefined
Which of the following is NOT a valid variable name in JavaScript?
A). _myVariable
B). 2ndVariable
C). $myVariable
D). my-Variable
Which symbol is used for string concatenation in JavaScript?
A). +
B). -
C). *
D). /
Which data type is used to represent whole numbers in JavaScript?
A). number
B). integer
C). float
D). string
What is the purpose of the NaN (Not a Number) value in JavaScript?
A). To represent a number that is not a valid JavaScript number
B). To represent a zero value
C). To represent an infinite value
D). To represent an empty string
Which method is used to convert a string to a number in JavaScript?
A). toString()
B). parseInt()
C). parseFloat()
D). toNumber()
What is the keyword used to declare variables in JavaScript?
A). let
B). variable
C). var
D). const
What is the scope of a variable declared using the let keyword in JavaScript?
A). Block scope
B). Function scope
C). Global scope
D). Local scope