w3resource

JavaScript substring Method: String Object

Description

The substring() method is used to extract a part from a specified string between two given indices.

Version

Implemented in JavaScript 1.0

Syntax

substring(ind1, ind2)

Parameter

ind1, ind2 : An integer between 0 and 1 less than the length of the string.

Note: The substring() extracts characters from ind1 upto but not including ind2.

  • If ind1 is less than 0 then ind1 automatically set to 0.
  • If ind2 is greater than the string length then ind2 automatically set to the length of the string.
  • The function returns an empty string if ind1 is equal to ind2.
  • If ind2 is not mentioned, ind1 extracts characters to the end of the string.

Example:

The following web document demonstrates how the substring() method can be used in various ways.

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=iso-8859-1" />
<title>JavaScript String object - substring() method example</title>
</head>
<body>
<h1 style="color: red">JavaScript String object : substring() method</h1>
<hr />
<script type="text/javascript">
//This is done to make the following JavaScript code compatible to XHTML. <![CDATA[
var str="Javascript"
document.write(str.substring(0,3)+"<br>")
document.write(str.substring(4,7)+"<br>")
document.write(str.substring(7,4)+"<br>")
document.write(str.substring(0,10))
//]]>
</script>
</body>
</html>

View the example 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.

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JavaScript: Tips of the Day

How to check whether a string contains a substring in JavaScript?

ECMAScript 6 introduced String.prototype.includes:

const string = "foo";
const substring = "oo";

console.log(string.includes(substring));

includes doesn't have Internet Explorer support, though. In ECMAScript 5 or older environments, use String.prototype.indexOf, which returns -1 when a substring cannot be found:

var string = "foo";
var substring = "oo";

console.log(string.indexOf(substring) !== -1);

Ref: https://bit.ly/3fFFgZv