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JavaScript replace() Method: String Object

Description

The replace() method is used to find a match between a regular expression and a string and replaces the matched substring (within the main string) with a given string.

Version

Implemented in JavaScript 1.2

Syntax

replace(regExp, newStr)

Parameter

regExp: Name of the regular expression.

newStr: The string replaces the matched substring in the main string found with regexp.

Example:

The following web document demonstrates how the replace() method can be used.

<!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 - replace() method example</title>
</head>
<body>
<h1 style="color: red">JavaScript String object : replace() method</h1>
<hr />
<script type="text/javascript">
//This is done to make the following JavaScript code compatible to XHTML. <![CDATA[
regex = /brown/gi;
str1 = "The Quick Brown Fox Jumps Over The Lazy Dog";
document.write("Original string : "+str1+"<br />");
document.write("Searched string : brown"+"<br />");
document.write("New string : white "+"<br />");
newstr=str1.replace(regex, "white");
document.write(newstr) 
//]]>
</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