Javascript interview questions part 22
Javascript interview questions part 22
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Total Questions: 20
1. When does a memory leak happen?
Correct Answer is : Browser doesn’t release memory from objects unnecessary
2. What will happen when the data of the jQuery.cache is read from an element?
Correct Answer is : Unique number is retrieved as elem[jQuery.expando] & Data is read from jQuery.cache[id]
3. The style property belongs to while of the following object?
Correct Answer is : Element
4. Which of the following functions are referenced internally?
Correct Answer is : both setTimeout and setInterval
5. What is the purpose of destroying the functions and objects?
Correct Answer is : All of the mentioned
6. When does a cycle occur during memory leak?
Correct Answer is : Two objects reference
7. Which of the following is a way to retain an object in memory?
Correct Answer is : Console Log
8. How many default number methods are available in JavaScript?
Correct Answer is : 7
9. What is an observer effect?
Correct Answer is : Observing influences outcome
10. Which of the following are ways to benchmark code?
Correct Answer is : Timing the code & Calculating the number of operations performed
11. How to calculate the run time of a code?
Correct Answer is : End time – Start time
12. According to the workflow of a runtime logging, what happens after calculating the run time?
Correct Answer is : Either Display to screen or Log to server
13. Which of the following object is used to post the data to an external process, say savePerfData?
Correct Answer is : XHR
14. Where does the external process save the result of the test?
Correct Answer is : Flat file
15. Which function is used to start the time logging?
Correct Answer is : startTimeLogging()
16. Which of the following attribute of form tag is not set by using document object in JavaScript?
Correct Answer is : None of the mentioned
17. What will be result of following javascript function?
Correct Answer is : Sanfoundry The Best
18. What type of scope is present in JavaScript?
Correct Answer is : Lexical
19. Which function is used to stop the time logging?
Correct Answer is : stopTimeLogging()
20. The lexical scooping in JavaScript is based on which of the following?
Correct Answer is : Functions
