A) JavaScript is a markup language

B) JavaScript is a scripting language

C) JavaScript is same as Java

D) JavaScript is compiled
langage

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Answer is B)
JavaScript is a scripting language, which can be used on client on server side.
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A) True
B) False

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Answer is A)
JavaScript is single-threaded.
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A) True
B) False

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Answer is B)
JavaScript is single threaded and has a synchronous execution model.
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A) Yes
B) No

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Answer is A)
JavaScript can be used for backend development using Node.js.
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A) let
B) var

C) const

D) constant

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Answer is C)
The const keyword is used to declare a variable as a constant type in Javascript, e.g.:

                
                    const pieValue=3.14
                
            

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        let a='3';
        console.log(a+3);
    

A) Error




B) 33


C) 6

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Answer is B)
As you have a string datatype first, any variable that comes after the “+” operator it will be concatenated
to your data, i.e “33”.

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A)
variable a;




B)
constant a;



C)
var a;



D)
lat a;

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Answer is C)
We can declare a variable using var or let or const, etc.

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A) True




B) False

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Answer is A)
All JavaScript identifiers are case sensitive.
e.g. fistName and firstname both are different variables.

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                var val1='JavaScript';
                var val1='JSDevLife';
                console.log(val1);
            
        

A) // SyntaxError: ‘val1’ has already been declared




B) JavaScript


C) JSDevLife

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Answer is C)
If we use var then we can redeclare it, and it will take last updated value so it prints JSDevLife.

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                let val1='JavaScript';
                let val1='JSDevLife';
                console.log(val1);
            
        

A) // SyntaxError: ‘val1’ has already been declared




B) JavaScript


C) JSDevLife

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Answer is A)
Variables defined with let cannot be redeclared.

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