JavaScript replace String

The JavaScript replace function to search for a specified string and update the searched substring with the newly specified string. The syntax of the string replace is

String_Object.replace(String_you_want_to_change, Replacing_String)
  • String_Object to perform a search. It will update a portion of a string.
  • Substring you want to change: Whatever you place here, and the function will change it with a new string.
  • Replacing_String: Substring you want to insert into the String_Object.

JavaScript replace String Example

This example will help you understand the String replace function.

The third statement finds substring ‘abc’ and substitute it with ‘JavaScript’ . If you observe the below screenshot, Although the ‘abc’ substring is repeated twice in Str2, this Function is changing the first occurrence.

In the next line, we used a regular expression to search for the substring ‘abc’ globally. So, this function substitute every occurrence of the word ‘abc’ with ‘JavaScript‘.

Next, using regular expression gi to perform the case-insensitive search.

<!DOCTYPE html>
    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 \>");