JavaScript

1. Java Script Module 2. World Wide Web (WWW) 3. Web Terms 4. NEED FOR SCRIPT 5. Introduction to Internet Programming 6. CLIENT SIDE and SERVER SIDE Scripting 7. Different Scripting Languages 8. Introduction to JavaScript 9. JavaScript and Security 10. How to Enable JavaScript 11. Advantages of Java Script 12. Limitations with JavaScript 13. Difference between JavaScript and JAVA 14. Difference between JavaScript and VBScript 15. JavaScript Development Tools 16. JavaScript Programming Techniques 17. JavaScript terms 18. Starting with JavaScript Programming step by step 19. Time to start JavaScript Programming 20. JavaScript Variables 21. JavaScript RESERVED WORDS 22. JavaScript Data Type 23. NUMBER DATA TYPE 24. BOOLEAN DATA TYPE 25. STRING DATA TYPE 26. NULL DATA TYPE 27. JavaScript Undefined DATA TYPE 28. JavaScript Operators 29. JavaScript Arithmetic Operators 30. JavaScript Logical Operators 31. JavaScript Comparison Operators 32. JavaScript String Operators 33. Bit Manipulation Operators 34. JavaScript Assignment Operators 35. JavaScript Conditional Operator 36. Conversion between JavaScript Data Types 37. Alert JavaScript function 38. confirm JavaScript function 39. prompt JavaScript function 40. JavaScript Statements 41. Single line & Multi-line Comments 42. JavaScrip If Statement 43. JavaScript if..else Statements 44. JavaScript If…else..if statement. 45. JavaScript For Statement 46. JavaScript For..in Statement: 47. JavaScript While Statement 48. JavaScript do while Statement: 49. JavaScript break and continue statement 50. JavaScript switch Statement: 51. JavaScript function() 52. JavaScript function with a Return Value 53. JavaScript with Statement 54. try, catch, and throw Statements 55. JavaScript ARRAY 56. JavaScript array of different data types 57. JavaScript ARRAY and Bubble sorting Program 58. JavaScript Array Methods 59. concate() method 60. every() method 61. filter() method 62. forEach() method 63. indexOf() method 64. Join() method 65. lastIndexOf() method 66. map() method 67. reduce() method 68. reduceRight() method 69. reverse() method 70. some() method 71. toSource() method 72. toString() method 73. pop() method 74. push() method 75. shift () method 76. slice () method 77. splice () method 78. sort() method 79. unshift() method 80. EVENT handling with JavaScript 81. onblur JavaScript Event 82. onchange JavaScript Event 83. onclick JavaScript Event 84. onDblClick JavaScript Event 85. onfocus JavaScript Event 86. onkeydown JavaScript Event 87. onkeyup JavaScript Event 88. Onkeypress JavaScript Event 89. onLoad JavaScript Event 90. onMousedown JavaScript Event 91. onMouseup JavaScript Event 92. Onmouseover JavaScript Event 93. onmouseout JavaScript Event 94. onMouseMove JavaScript Event 95. onReset JavaScript Event 96. onsubmit JavaScript Event 97. onUnload JavaScript Event 98. The Screen Object 99. JavaScript Interview Part1 100. JavaScript Interview Part2 101. JavaScript Interview Part3 102. JavaScript Interview Part4 103. JavaScript Interview Part5 104. JavaScript Interview Part6 105. JavaScript Interview Part7 106. JavaScript Interview Part8 107. JavaScript Interview Part9 108. JavaScript Interview Part10
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JavaScript Interview Questions and Answers Part 3

 

21. How to set the focus in an element using Javascript?

  • Example: To set the focus in an element using Javascript

<script type="text/javascript">

function setFocus() {

if(focusElement != null)

{

document.forms[0].elements["myelementname"].focus();

}

}

</script>

 

22. How to access an external javascript file that is stored externally and not embedded?

  • This can be achieved by using the following tag between head tags or between body tags.

  • <script src="abc.js">

  • </script>

  • where abc.js is the external javscript file to be accessed.

 

23. Are javascript and jQuery different?

  • jQuery is a quick as well as concise JavaScript Library that simplifies HTML document traversing, animating, event handling, & Ajax interactions for the purpose of quick web development needs.

  • So although they are not entirely different, both are not the same either!

 

24. Difference between window.onload and onDocumentReady?

  • The onload event does not fire until every last piece of the page is loaded, this includes css and images, which means there’s a huge delay before any code is executed.

  • That isnt what we want. We just want to wait until the DOM is loaded and is able to be manipulated. onDocumentReady allows the programmer to do that.

 

25. What is a prompt box?

  • The JavaScript prompt box prompts the user to input text. The 'prompt' box is created using JavaScript's built-in prompt() function.

  • When the JavaScript prompt() function is triggered, a small box will pop up and display a message to the user (supplied by you), a text field (for the user's input), an "OK" button, and a "Cancel" button.

  • If the user clicks "OK" the box returns the input value. If the user clicks "Cancel" the box returns null.

  • Syntax:

  • General syntax of prompt box is as follows:

propmpt (“textmessage”,”default_value”)

 

26. Can javascript code be broken in different lines?

  • Breaking is possible within a string statement by using a backslash \ at the end but not within any other javascript statement.

  • that is ,

  • document.write("Hello \ world");

  • is possible but not document.write \

  • ("hello world");

 

27. What looping structures are there in JavaScript?

  • for, while, do-while loops, but no foreach.

 

28. How do you create a new object in JavaScript?

  • var obj = new Object();

  • or var obj = {};

 

29. What is this keyword?

  • The JavaScript this keyword is used within any function scope or the global scope, and in each scope it receives a different value.

  • The value of this inside a function, effectively depends on the object which called it.

  • Scope? Every function gets its own space in order to define variables and properties.

  • When we want to access a certain variable, we must do it through the space in which it was defined. In JavaScript, when we haven’t defined a function, everything happens in global scope.

 

30. What is the difference between SessionState and ViewState?

  • ViewState is specific to a page in a session. Session state refers to user specific data that can be accessed across all pages in the web application.

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