JavaScript indexOf() Method: String Object


The indexOf() method returns the index within the calling string object of the first occurrence of the specified value, starting the search at startIndex. It returns -1 if the value is not found.


Implemented in JavaScript 1.0


indexOf(searchValue, startIndex) 


searchValue: A string representing the value to search for.

startIndex  : The location in the string to search the specified value. Location value is an integer between 0 and the length of the string. The default value is 0.

Example of String object: indexOf() Method

In the following web document indexOf() method is used to locate values in a given string.

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<meta http-equiv="content-type" content="text/html; charset=iso-8859-1" />
<title>JavaScript String object - indexOf() method example</title>
<h1 style="color: red">JavaScript String object : indexOf() method</h1>
<hr />
<script type="text/javascript">
//This is done to make the following JavaScript code compatible to XHTML. <![CDATA[
var Str="Brave new world"
document.write("The index of the first w from the beginning is " +
Str.indexOf("w")+"<br />")
document.write("The index of 'new' from the beginning is " +

View the example of String object's indexOf method in the browser

Supported Browser

Internet Explorer 7 Firefox 3.6 Google Chrome 7 Safari 5.0.1 Opera 10
Yes Yes Yes Yes Yes

See also:

JavaScript Core objects, methods, properties.

Previous: JavaScript fromCharCode() Method: String Object
Next: JavaScript italics() Method: String Object

Test your Programming skills with w3resource's quiz.

Follow us on Facebook and Twitter for latest update.