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
Pr.Pg Next Pg

indexOf() JavaScript Array method tutorials

  • The Javascript array indexOf() method returns the position of the first occurrence of a specified value in the array. And this method returns -1 if the value to search for never occurs.

 

Syntax:

array.indexOf (searchvalue [, fromIndex] );

searchvalue: value  to locate in the array.

fromIndex : The index at which to begin the search. Defaults to 0, i.e. the whole array will be searched. If the index is greater than or equal to the length of the array, -1 is returned.

 

  • Browser Compatibility: The indexOf() method is supported in all major browsers. Like Internet Explorer, Chrome, Firefox, Opera, Safari.

 

Example: JavaScript example to show how to use the indexOf() method with an array.
Output:

The First position of sam = 14

The position of the second sam = 34

 

  • From the above example, If we use the indexOf function to find the first "sam", then we can use that position + 1 as a way to skip the first "sam" and find the second.

 

Example: JavaScript example to show how to use the indexOf method() with an array.
Output:

24 value is found at index : 4

30 value is found at index : -1

 

  • From the above example, we have array [9, 20, 6, 10, 24]. Now we want to find the indexOf(24), which is at the position 4.

  • Now if I want to find indexOf(25) does not belong to the array then the output will be -1, which is shown in the above output. Negative value means that value is not found in Array.

 

Pr.Pg border                                              Next Pg