Which method is used to convert a string to a number in JavaScript?
A). toString()
B). parseInt()
C). parseFloat()
D). toNumber()
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 keyword is used to declare a constant variable in JavaScript?
A). const
B). let
C). var
D). constant
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 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
Which data type is used to represent whole numbers in JavaScript?
A). number
B). integer
C). float
D). string
Which symbol is used for string concatenation in JavaScript?
A). +
B). -
C). *
D). /
What will be the output of the following code: console.log(typeof 'Hello');?
A). string
B). number
C). undefined
D). boolean
What will be the output of the following code: console.log(parseInt('10.5'));?
A). 10
B). 5
C). '10.5'
D). NaN (Not a Number)
Which of the following is NOT a valid variable name in JavaScript?
A). _myVariable
B). 2ndVariable
C). $myVariable
D). my-Variable