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
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 variable declaration is appropriate if you want a variable to hold a constant value throughout the program execution?
A). let
B). var
C). const
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'
Which statement correctly assigns the value true to a boolean variable isLogged in JavaScript?
A). let isLogged = 'true';
B). let isLogged = true;
C). let isLogged = 1;
D). let isLogged = 0;
Which data type is used to represent whole numbers in JavaScript?
A). number
B). integer
C). float
D). string
Which of the following is NOT a valid variable name in JavaScript?
A). _myVariable
B). 2ndVariable
C). $myVariable
D). my-Variable
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('Hello ' + 'World');?
A). Hello World
B). Hello + World
C). Hello +World
D). HelloWorld
Which symbol is used for string concatenation in JavaScript?
A). +
B). -
C). *
D). /