85 JAVASCRIPT Interview Questions

While different interviewers may ask distinctive questions, it always helps to be prepared for severe grilling. So we have to drawn up a list of frequently asked 85 javascript interview questions. Read all the questions and prepare answers dotted with examples for success in the job interview.

  1. What is JavaScript?
  2. How is JavaScript different from Java?
  3. What is relationship between JavaScript and ECMAScript?
  4. How do you submit a form using Javascript?
  5. How do we get JavaScript onto a web page?
  6. How to detect the operating system on the client machine?
  7. How to read and write a file using javascript?
  8. How can JavaScript make a Web site easier to use? That is, are there certain JavaScript techniques that make it easier for people to use a Web site?
  9. How can JavaScript be used to improve the "look and feel" of a Web site?
  10. How can JavaScript be used to improve the user interface?
  11. What are JavaScript types?
  12. How to create arrays in JavaScript?
  13. How do you convert numbers between different bases in JavaScript?
  14. What is a fixed-width table and its advantages?
  15. Where are cookies actually stored on the hard disk?
  16. How do you target a specific frame from a hyperlink?
  17. What can javascript programs do?
  18. How to set a HTML document's background color?
  19. How to add Buttons in JavaScript?
  20. Are you concerned that older browsers do not support JavaScript and thus exclude a set of Web users? individual users?
  21. What is the data type of variables of in JavaScript?
  22. What is negative infinity?
  23. In a pop-up browser window, how do you refer to the main browser window that opened it?
  24. What does isNaN function do?
  25. What Boolean operators does JavaScript support?
  26. What and where are the best JavaScript resources on the Web?
  27. How to write a script for "Select" lists using javascript
  28. What does the "Access is Denied" IE error mean?
  29. Is a javascript script faster than an ASP script?
  30. How to embed javascript in a web page?
  31. Are Java and JavaScript the Same?
  32. What are the problems associated with using JavaScript, and are there JavaScript techniques that you discourage?
  33. What does "1"+2+4 evaluate to?
  34. What does the EnableViewStateMac setting in an aspx page do?
  35. What is the difference between SessionState and ViewState?
  36. Taking a developer’s perspective, do you think that that JavaScript is easy to learn and use?
  37. What is a prompt box?
  38. What is the difference between an alert box and a confirmation box?
  39. Can javascript code be broken in different lines?
  40. What looping structures are there in JavaScript?
  41. How to hide javascript code from old browsers that dont run it?
  42. How to Accessing Elements using javascript?
  43. How to comment javascript code?
  44. What does javascript null mean?
  45. Name the numeric constants representing max,min values
  46. What’s a way to append a value to an array?
  47. How do you assign object properties?
  48. To set all checkboxes to true using JavaScript?
  49. How to select an element by id and swapping an image?
  50. What does the term sticky session mean in a web-farm scenario? Why would you use a sticky session? What is the potential disadvantage of using a sticky session?
  51. What is === operator?
  52. Does javascript have the concept level scope?
  53. What are undefined and undeclared variables?
  54. What is variable typing in javascript?
  55. What is the difference between undefined value and null value?
  56. What does undefined value mean in javascript?
  57. How to disable an HTML object?
  58. How to Add new elements dynamically?
  59. To write messages to the screen without using "document.write()" ?
  60. How to find radio button selection when a form is submitted?
  61. How to find the selected radio button immediately using the 'this' variable?
  62. How to setting a cookie with the contents of a textbox?
  63. How to create a popup warning box?
  64. How to create a confirmation box?
  65. How to getting values from cookies to set widgets?
  66. How to change style on an element?
  67. How to Handle Event Handlers?
  68. How to remove the event listener: ?
  69. How to reload the current page?
  70. How to make elements invisible?
  71. how to force a page to go to another page using JavaScript?
  72. How to set the cursor to wait?
  73. How to convert a string to a number using JavaScript?
  74. How to test for bad numbers using JavaScript?
  75. How to convert numbers to strings using JavaScript?
  76. How to create Arrays using JavaScript?
  77. What does the delete operator do?
  78. How to delete an entry using JavaScript?
  79. How to use strings as array indexes using JavaScript?
  80. How to make a array as a stack using JavaScript?
  81. How to shift and unshift using JavaScript?
  82. How to create an object using JavaScript?
  83. How to associate functions with objects using JavaScript?
  84. What's Prototypes for JavaScript?
  85. How to create a function using function constructor?