JavaScript Multiple Choice Questions

21. What is defination of an undefined value in JavaScript?

A. Variable used in the code doesn't exist
B. Variable is not assigned to any value
C. Property doesn't exist
D. All of the above

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22. What are the types of Pop up boxes available in JavaScript?

A. Alert
B. Prompt
C. Confirm
D. All of the above

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23. what is the disadvantage of using innerHTML in JavaScript?

A. Content can not be replaced everywhere
B. We can use like "appending to innerHTML"
C. Even if you use +=like "innerHTML = innerHTML + 'html'" still the old content is replaced by html
D. The entire innerHTML content is not re-parsed and build into elements, therefore its not slower

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24. What are the two basic groups of dataypes in JavaScript?

A. Primitive
B. Reference types.
C. All of the above
D. None of the above

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25. Which of the following are the errors in JavaScript?

A. Load time errors
B. Run time errors:
C. Logical Errors:
D. All of the above

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26. Which of the following are the functional components in JavaScript?

A. First-class functions
B. Encapsulated-class functions
C. Fixed-class functions
D. All of the above

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27. Which of the following is not the properties of screen objects in JavaScript?

A. AvailHeight
B. ColorsDepth
C. AvailWidth
D. ColorDepth

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28. Javascript string using double quotes is exactly the same as a string using single quotes?

A. True
B. False

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29. Find output of below code
var a = '20';
var b = a = 30;

A. Error in Script
B. '20'30
C. 2030
D. 50

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30. What is divide by 0 in Javascript? var a = 10;
var b = 0;

A. Nothing is printed
B. 0 is printed
C. Infinity is printed
D. Some Garbage Value

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