The JavaScript Replace function search for a specified string and replace the searched string with the newly specified string. The syntax of the string Replace in JavaScript is
String_Object.replace(String you want to change, Replacing_String)
- String_Object to perform a search. Replace function will replace a portion of a string present in this String_Object.
- String you want to change: Whatever you place here, Javascript string replace Function will replace it with a new string
- Replacing_String: New string you want to insert into the String_Object.
JavaScript Replace String Example
This example 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>

It finds substring ‘abc’ and substitute it with substring ‘JavaScript’ . If you observe the above screenshot, Although ‘abc’ substring is repeated twice in Str2, the Replace String Function is replacing the first occurrence
var Str3 = Str2.replace("abc","JavaScript");
In the next JavaScript line, we used a regular expression to search for the substring ‘abc’ globally. So, string Replace() function replace every occurrence of the word ‘abc’ with ‘JavaScript’
var Str4 = Str2.replace(/abc/g,"JavaScript");
Using regular expression gi to perform the case-insensitive search
var Str6 = Str1.replace(/abc/gi,"JavaScript");