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1. What is the difference between the operators '==' and '==='?
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2. What is an ECMAScript?
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3. What is DOM?
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4. What is the difference between innerHTML and innerText?
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5. What is the difference between null and undefined in JavaScript?
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6. How could you set a prefix before everything you log?
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7. What are falsy and truthy values?
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8. How do you check if an object is an array or not?
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9. What is the difference between the postfix i++ and prefix ++i increment operators?
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10. What is the instanceof operator in JavaScript?
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11. What would be the result of 3+2+”7″?
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12. What is AJAX?
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13. Is ‘false’ false?
medium
14. You have a for loop if you have setTimeout inside it. If log the loop counter inside setTimeout, what will be logged?
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15. What is the difference between slice and splice?
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16. What is the default unit of difference of two dates?
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17. What is hoisting in JavaScript?
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18. What types of functions does JavaScript support?
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19. What is the difference between the substr() and substring() functions in JavaScript?
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20. How would you swap two numbers without using a temporary variable?
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21. What are all the types of Pop up boxes available in JavaScript?
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22. How many ways we get the element in javascript?
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23. What kind of loops are in JavaScript?
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24. What is the difference between JSON.stringify and JSON.parse?
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25. How to handle exception in JavaScript?
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26. What is the difference between undeclared and undefined variables?
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27. Name some Javascript functions used to convert non numerical values into numbers.
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28. What is a closure in Javascript?
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29. What does isNaN function do?
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30. What are the different types of errors in JavaScript?
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31. How to access JSON object in JavaScript?
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32. What is the different between Statically typed and Dynamically Typed?
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33. How to check function exists before calling it?
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34. What is the difference between window.onload and onDocumentReady?
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35. How To Remove All Odd Numbers In An Array Using Javascript?
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36. What is the difference between ‘Function’ and ‘function’?
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37. How would you reverse a string in JavaScript?
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38. What is Hoisting?
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39. What is the difference between JSON.stringify and JSON.parse?
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40. What is the difference between window, screen, and document in JavaScript?
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41. What is the difference between the function declarations below?
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42. What is the only value not equal to itself in JavaScript?
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43. Difference between: function Person(){}, var person = Person(), and var person = new Person()?
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44. How to get array of object property value to a new array?
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45. Explain what a callback function is and why do we need?
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46. Can you name two programming paradigms important for JavaScript app developers?
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47. When is prototypal inheritance an appropriate choice?
hard
48. What is prototypical inheritance and how useful is it?
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49. What does a JavaScript function result when it has no return statement?
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50. What is the drawback of creating true private methods in JavaScript?
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51. What are promises and how they are useful?
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52. How to check whether a key exist in a JavaScript object or not?
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53. What does 0.1 + 0.2 === 0.3 evaluate to?
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54. What's the difference between JavaScript, JScript & ECMAScript?
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55. Explain the difference between a static method and an instance method.
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56. What is the only value not equal to itself in JavaScript?
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57. What is the difference between synchronous and asynchronous code in JavaScript?
hard
58. Why does 3 + true = 4?
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59. Write code to sum a property value in an array.