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JavaScript Replace String

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The JavaScript Replace function is one of the String Function which is used to search for specified string and replace the searched string with newly specified string.

In this article, we will show you, How to write string Replace in JavaScript Programming Language with example.

The basic syntax of the string Replace in JavaScript Programming is as shown below:

String_Object.replace(String you want to change, Replacing_String)
  • String_Object: Please specify the valid string to perform search. Replace function will replace portion of a string present in this String_Object.
  • String you want to change: Please specify a valid string or Regular expression you want to change. Whatever you place here, Javascript string replace Function will be replace it by new string
  • Replacing_String: Please provide a valid new string you want to insert into the String_Object.

JavaScript Replace String Example

The following set of examples will help you understand the String Replace function.

<!DOCTYPE html>
<html>
<head>
    <title> Replace in JavaScript </title>
</head>
<body>
    <h1> JavaScript Replace()</h1>
<script>
    var Str1 = "We are ABC working at abc company";
    var Str2 = "We are abc working at abc company";
    var Str3 = Str2.replace("abc","JavaScript");
    var Str4 = Str2.replace(/abc/g,"JavaScript");
    var Str5 = Str1.replace("abc","JavaScript");
    var Str6 = Str1.replace(/abc/gi,"JavaScript");
 
    document.write(Str3 + "<br \>");
    document.write(Str4 + "<br \>");
    document.write(Str5 + "<br \>");
    document.write(Str6 + "<br \>");
</script>
</body>
</html>

OUTPUT

JavaScript REPLACE Function

ANALYSIS

Within the replace function Script tag, First we declared two String variables Str1, Str2 and assigned corresponding values using following statement

 var Str1 = "We are ABC working at abc company";
 var Str2 = "We are abc working at abc company";

he following statement will find the sub string ‘abc’ and replace the string with substring ‘JavaScript’ . If you observe the above screenshot, Although ‘abc’ sub string is repeated twice in Str2 variable, Replace() function is replacing the first occurrence

var Str3 = Str2.replace("abc","JavaScript");

In the next line, we used the regular expression to search for the substring ‘abc’ globally. So, string Replace() function will replace each and every occurrence of the word ‘abc’ with ‘JavaScript’

var Str4 = Str2.replace(/abc/g,"JavaScript");

In order to perform case-insensitive search, the following statement is using regular expression gi

var Str6 = Str1.replace(/abc/gi,"JavaScript");

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