JavaScript, often abbreviated as JS, is a programming language that is one of the core technologies of the World Wide Web, alongside HTML and CSS. As of 2023, 98.7% of websites use JavaScript on the client side for webpage behavior, often incorporating third-party libraries. (Source: JavaScript)

JavaScript makes web pages interactive. It allows web developers to create dynamically updating content, use animations, pop-up menus, clickable buttons, control multimedia, etc.

JavaScript Knowledge Test

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25 Questions

1. In JavaScript, what is the return value for the following code:[1, 2, 3, 4].shift()?

2, 3, 4141, 2, 3

2. In JavaScript, what operator allows you to create a function that takes a variable number of arguments?

Rest operatorDivision OperatorMultiplication OperatorSpread operator

3. In JavaScript, what method is used to arrange array values into descending order?

reverse()unshift()from()join()

4. What JavaScript keyword will return the type of a variable when you call it?

datatypevarthistypeof

5. In JavaScript, what is the name of the process that moves variables, functions, and classes to the top of the scope?

AwaitHoistingSetterBreak

6. In JavaScript, what is the range of numbers returned from the Math.random() method?

Between 0 and 1 (including 1; not including 0).Between 0 and 1 (including neither 0 or 1).Between 0 and 1 (including 0; not including 1).Between 0 and 100 (including 0; not including 100).

7. In JavaScript, what is the difference between == and ===?

== allows for type coercion of the values, while === does not== and === both allow for type coercion of the values== does not allow for type coercion of the values

8. In JavaScript, which method returns an HTMLCollection object that consists of all of the elements that have the same class name?

getElementsByTagName()getElementsByClassName()querySelector()getElementsByName()

9. In JavaScript, all objects inherit a built-in property from a ___________________.

nodeprototypeinstance variableaccessor

10. In JavaScript, which method creates a new array and returns all of the items which pass the condition specified in the callback?

filter()flat()split()concat()

11. In JavaScript, how do you write an inline comment?

<!-- Comment --># Comment// Comment/* Comment

12. In JavaScript, which Web API is used to display a dialog box with an optional message?

window.alertContent()window.alertHTML()window.alertBox()window.alert()

13. In JavaScript, what value is returned by default when a function doesn't have a return statement?

0Noneconcatundefined

14. In JavaScript, which of the following is a commonly used web API?

consolelet, var, constObjectArray

15. In JavaScript, how many threads does code run in?

Single threadCan be both single threaded and multi-threadedMultiple threadsNo threads

16. In HTML, what are

 

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