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Examples

Search a string for "welcome":

let text = "Hello world, welcome to the universe.";
let result = text.indexOf["welcome"];

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Search a string for "Welcome":

let text = "Hello world, welcome to the universe.";
let result = text.indexOf["Welcome"];

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Find the first occurrence of "e":

let text = "Hello world, welcome to the universe.";
text.indexOf["e"];

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Find the first occurrence of "e", starting at position 5:

let text = "Hello world, welcome to the universe.";
text.indexOf["e", 5];

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Find the first occurrence of "a":

let text = "Hello world, welcome to the universe.";
text.indexOf["a"];

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Definition and Usage

The indexOf[] method returns the position of the first occurrence of a value in a string.

The indexOf[] method returns -1 if the value is not found.

The indexOf[] method is case sensitive.

Syntax

string.indexOf[searchvalue, start]

Parameters

Return Value

The Differense Between
String indexOf[] and String search[]

The indexOf[] method cannot search against a regular expression.

The search[] cannot take a start position argument.

Browser Support

indexOf[] is an ECMAScript1 [ES1] feature.

ES1 [JavaScript 1997] is fully supported in all browsers:

Examples

Find the first index of "Apple":

const fruits = ["Banana", "Orange", "Apple", "Mango"];
let index = fruits.indexOf["Apple"];

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Start at index 3:

const fruits = ["Banana", "Orange", "Apple", "Mango", "Apple"];
let index = fruits.indexOf["Apple", 3];

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More examples below.

Definition and Usage

The indexOf[] method returns the first index [position] of a specified value.

The indexOf[] method returns -1 if the value is not found.

The indexOf[] method starts at a specified index and searches from left to right.

By default the search starts at the first element and ends at the last.

Negative start values counts from the last element [but still searches from left to right].

Syntax

array.indexOf[item, start]

Parameters

Return Value

Note

In an array, the first element has index [position] 0, the second has index 1, ...

More Examples

Find the first index of "Apple", starting from the last element:

const fruits = ["Banana", "Orange", "Apple", "Mango", "Apple"];
let index = fruits.indexOf["Apple", -1];

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Browser Support

indexOf[] is an ECMAScript5 [ES5] feature.

ES5 [JavaScript 2009] fully supported in all browsers:

array.indexOf [element,index]

DOCTYPE html>




  
var a = ["GOLD","SILVER","DIAMOND","RUBY","PLATINUM"]	 
var result=a.indexOf["DIAMOND"];  
document.writeln[result];